HTML

Living Standard — Last Updated 4 December 2019

1. 6 User interaction
   1. 6.1 The hidden attribute
   2. 6.2 Inert subtrees
   3. 6.3 Tracking user activation
      1. 6.3.1 Data model
      2. 6.3.2 Processing model
      3. 6.3.3 APIs gated by user activation
   4. 6.4 Activation behavior of elements
   5. 6.5 Focus
      1. 6.5.1 Introduction
      2. 6.5.2 Data model
      3. 6.5.3 The tabindex attribute
      4. 6.5.4 Processing model
      5. 6.5.5 Sequential focus navigation
      6. 6.5.6 Focus management APIs
      7. 6.5.7 The autofocus attribute
   6. 6.6 Assigning keyboard shortcuts
      1. 6.6.1 Introduction
      2. 6.6.2 The accesskey attribute
      3. 6.6.3 Processing model
   7. 6.7 Editing
      1. 6.7.1 Making document regions editable: The contenteditable content attribute
      2. 6.7.2 Making entire documents editable: the designMode IDL attribute
      3. 6.7.3 Best practices for in-page editors
      4. 6.7.4 Editing APIs
      5. 6.7.5 Spelling and grammar checking
      6. 6.7.6 Autocapitalization
      7. 6.7.7 Input modalities: the inputmode attribute
      8. 6.7.8 Input modalities: the enterkeyhint attribute

6 User interaction

6.1 The hidden attribute

All HTML elements may have the hidden content attribute set. The hidden attribute is a boolean attribute. When specified on an element, it indicates that the element is not yet, or is no longer, directly relevant to the page's current state, or that it is being used to declare content to be reused by other parts of the page as opposed to being directly accessed by the user. User agents should not render elements that have the hidden attribute specified. This requirement may be implemented indirectly through the style layer. For example, an HTML+CSS user agent could implement these requirements using the rules suggested in the Rendering section.

Because this attribute is typically implemented using CSS, it's also possible to override it using CSS. For instance, a rule that applies 'display: block' to all elements will cancel the effects of the hidden attribute. Authors therefore have to take care when writing their style sheets to make sure that the attribute is still styled as expected.

  <h1>The Example Game</h1>
  <section id="login">
   <h2>Login</h2>
   <form>
    ...
    <!-- calls login() once the user's credentials have been checked -->
   </form>
   <script>
    function login() {
      // switch screens
      document.getElementById('login').hidden = true;
      document.getElementById('game').hidden = false;
    }
   </script>
  </section>
  <section id="game" hidden>
   ...
  </section>

The hidden attribute must not be used to hide content that could legitimately be shown in another presentation. For example, it is incorrect to use hidden to hide panels in a tabbed dialog, because the tabbed interface is merely a kind of overflow presentation — one could equally well just show all the form controls in one big page with a scrollbar. It is similarly incorrect to use this attribute to hide content just from one presentation — if something is marked hidden, it is hidden from all presentations, including, for instance, screen readers.

Elements that are not themselves hidden must not hyperlink to elements that are hidden. The for attributes of label and output elements that are not themselves hidden must similarly not refer to elements that are hidden. In both cases, such references would cause user confusion.

Elements and scripts may, however, refer to elements that are hidden in other contexts.

Elements in a section hidden by the hidden attribute are still active, e.g. scripts and form controls in such sections still execute and submit respectively. Only their presentation to the user changes.

The hidden IDL attribute must reflect the content attribute of the same name.

6.2 Inert subtrees

This section does not define or create any content attribute named "inert". This section merely defines an abstract concept of inertness.

A node (in particular elements and text nodes) can be marked as inert. When a node is inert, then the user agent must act as if the node was absent for the purposes of targeting user interaction events, may ignore the node for the purposes of text search user interfaces (commonly known as "find in page"), and may prevent the user from selecting text in that node. User agents should allow the user to override the restrictions on search and text selection, however.

For example, consider a page that consists of just a single inert paragraph positioned in the middle of a body. If a user moves their pointing device from the body over to the inert paragraph and clicks on the paragraph, no mouseover event would be fired, and the mousemove and click events would be fired on the body element rather than the paragraph.

When a node is inert, it generally cannot be focused. Inert nodes that are commands will also get disabled.

While a browsing context container is marked as inert, its nested browsing context's active document, and all nodes in that Document, must be marked as inert.

An element is expressly inert if it is inert and its node document is not inert.

A Document document is blocked by a modal dialog subject if subject is the topmost dialog element in document's top layer. While document is so blocked, every node that is connected to document, with the exception of the subject element and its shadow-including descendants, must be marked inert. (The elements excepted by this paragraph can additionally be marked inert through other means; being part of a modal dialog does not "protect" a node from being marked inert.)

The dialog element's showModal() method causes this mechanism to trigger, by adding the dialog element to its node document's top layer.

6.3 Tracking user activation

To prevent abuse of certain APIs that could be annoying to users (e.g., opening popups or vibrating phones), user agents allow these APIs only when the user is actively interacting with the web page or has interacted with the page at least once. This "active interaction" state is maintained through the mechanisms defined in this section.

6.3.1 Data model

For the purpose of tracking user activation, each Window W has a last activation timestamp. This is a number indicating the last time W got an activation notification. It corresponds to a DOMHighResTimeStamp value except for two cases: positive infinity indicates that W has never been activated, while negative infinity indicates that a user activation-gated API has consumed the last user activation of W. The initial value is positive infinity.

A user agent also defines a transient activation duration, which is a constant number indicating how long a user activation is available for certain user activation-gated APIs (e.g., for opening popups).

The transient activation duration is expected be at most a few seconds, so that the user can possibly perceive the link between an interaction with the page and the page calling the activation-gated API.

These two values imply two boolean user activation states for W:

Sticky activation

When the current high resolution time is greater than or equal to the last activation timestamp in W, W is said to have sticky activation.

This is W's historical activation state, indicating whether the user has ever interacted in W. It starts false, then changes to true (and never changes back to false) when W gets the very first activation notification.

Transient activation

When the current high resolution time is greater than or equal to the last activation timestamp in W, and less than the last activation timestamp in W plus the transient activation duration, then W is said to have transient activation.

This is W's current activation state, indicating whether the user has interacted in W recently. This starts with a false value, and remains true for a limited time after every activation notification W gets.

The transient activation state is considered expired if it becomes false because the transient activation duration time has elapsed since the last user activation. Note that it can become false even before the expiry time through an activation consumption.

6.3.2 Processing model

When a user interaction in a browsing context B causes firing of an activation triggering input event in B's active document D, the user agent must perform the following activation notification steps before dispatching the event:

1. Let browsingContexts be a list consisting of:

   • B,

   • all ancestor browsing contexts of B, and

   • all the descendant browsing contexts of D that have active documents from the same origin as that of D.

2. Let windows be the list of Window objects constructed by taking the [[Window]] internal slot value of browsingContext's WindowProxy object for each browsingContext in browsingContexts.

3. For each window in windows, set window's last activation timestamp to the current high resolution time.

An activation triggering input event is any event whose isTrusted attribute is true and whose type is one of:

• change
• click
• contextmenu
• dblclick
• mouseup
• pointerup
• reset
• submit
• touchend

The event set is inconsistent across major browsers. See issue #3849.

Activation consuming APIs defined in this and other specifications can consume user activation by performing the following steps, given a Window W:

1. If W's browsing context is null, then return.

2. Let top be W's browsing context's top-level browsing context.

3. Let browsingContexts be the list of the descendant browsing contexts of top's active document.

4. Append top to browsingContexts.

5. Let windows be the list of Window objects constructed by taking the [[Window]] internal slot value of browsingContext's WindowProxy object for each browsingContext of browsingContexts.

6. For each window in windows, if window's last activation timestamp is not positive infinity, then set window's last activation timestamp to negative infinity.

The spec is not clear about how to traverse a tree of documents. See issue #5020.

Note the asymmetry in the sets of browsing contexts in the page that are affected by an activation notification vs an activation consumption: an activation consumption changes (to false) the transient activation states for all browsing contexts in the page, but an activation notification changes (to true) the states for a subset of those browsing contexts. The exhaustive nature of consumption here is deliberate: it prevents malicious sites from making multiple calls to an activation consuming API from a single user activation (possibly by exploiting a deep hierarchy of iframes).

6.3.3 APIs gated by user activation

APIs that are dependent on user activation are classified into three different levels. The levels are as follows, sorted by their "strength of dependence" on user activation (from weakest to strongest):

Sticky activation-gated APIs

These APIs require the sticky activation state to be true, so they are blocked until the very first user activation.

Transient activation-gated APIs

These APIs require the transient activation state to be true, but they don't consume it, so multiple calls are allowed per user activation until the transient state expires.

Transient activation-consuming APIs

These APIs require the transient activation state to be true, and they consume user activation in each call to prevent multiple calls per user activation.

6.4 Activation behavior of elements

Certain elements in HTML have an activation behavior, which means that the user can activate them. This is always caused by a click event.

The user agent should allow the user to manually trigger elements that have an activation behavior, for instance using keyboard or voice input, or through mouse clicks. When the user triggers an element with a defined activation behavior in a manner other than clicking it, the default action of the interaction event must be to fire a click event at the element.

element . click()

Acts as if the element was clicked.

Each element has an associated click in progress flag, which is initially unset.

The click() method must run the following steps:

1. If this element is a form control that is disabled, then return.

2. If this element's click in progress flag is set, then return.

3. Set this element's click in progress flag.

4. Fire a synthetic mouse event named click at this element, with the not trusted flag set.

5. Unset this element's click in progress flag.

6.5 Focus

6.5.1 Introduction

This section is non-normative.

An HTML user interface typically consists of multiple interactive widgets, such as form controls, scrollable regions, links, dialog boxes, browser tabs, and so forth. These widgets form a hierarchy, with some (e.g. browser tabs, dialog boxes) containing others (e.g. links, form controls).

When interacting with an interface using a keyboard, key input is channeled from the system, through the hierarchy of interactive widgets, to an active widget, which is said to be focused.

Keyboard events are always targeted at this focused element.

6.5.2 Data model

The term focusable area is used to refer to regions of the interface that can become the target of keyboard input. Focusable areas can be elements, parts of elements, or other regions managed by the user agent.

Each focusable area has a DOM anchor, which is a Node object that represents the position of the focusable area in the DOM. (When the focusable area is itself a Node, it is its own DOM anchor.) The DOM anchor is used in some APIs as a substitute for the focusable area when there is no other DOM object to represent the focusable area.

The following table describes what objects can be focusable areas. The cells in the left column describe objects that can be focusable areas; the cells in the right column describe the DOM anchors for those elements. (The cells that span both columns are non-normative examples.)

<map id=wallmap><area alt="Enter Door" coords="10,10,100,200" href="door.html"></map>
...
<img src="images/innerwall.jpeg" alt="There is a white wall here, with a door." usemap="#wallmap">
...
<img src="images/outerwall.jpeg" alt="There is a red wall here, with a door." usemap="#wallmap">

A browsing context container (e.g. an iframe) is a focusable area, but key events routed to a browsing context container get immediately routed to the nested browsing context's active document. Similarly, in sequential focus navigation a browsing context container essentially acts merely as a placeholder for its nested browsing context's active document.

One focusable area in each Document is designated the focused area of the document. Which control is so designated changes over time, based on algorithms in this specification.

Focusable areas in a Document are ordered relative to the tree order of their DOM anchors. Focusable areas with the same DOM anchor in a Document are ordered relative to their CSS boxes' relative positions in a pre-order, depth-first traversal of the box tree. [CSS]

The currently focused area of a top-level browsing context at any particular time is the focusable area returned by this algorithm:

1. Let candidate be the Document of the top-level browsing context.

2. If the designated focused area of the document is a browsing context container with a non-null nested browsing context, then let candidate be the active document of that browsing context container's nested browsing context, and redo this step.

3. If candidate has a focused area, set candidate to candidate's focused area.

4. Return candidate.

An element that is the DOM anchor of a focusable area is said to gain focus when that focusable area becomes the currently focused area of a top-level browsing context. When an element is the DOM anchor of a focusable area of the currently focused area of a top-level browsing context, it is focused.

The focus chain of a focusable area subject is the ordered list constructed as follows:

1. Let current object be subject.

2. Let output be an empty list.

3. Loop: Append current object to output.

4. If current object is an area element's shape, append that area element to output.

   Otherwise, if current object is a focusable area whose DOM anchor is an element that is not current object itself, append that DOM anchor element to output.

5. If current object is a Document in a nested browsing context, let current object be its browsing context container, and return to the step labeled loop.

6. Return output.

   The chain starts with subject and (if subject is or can be the currently focused area of a top-level browsing context) continues up the focus hierarchy up to the Document of the top-level browsing context.

All elements that are focusable areas are said to be focusable.

There are two special types of focusability for focusable areas:

• A focusable area is said to be sequentially focusable if it is included in its Document's sequential focus navigation order and the user agent determines that it is sequentially focusable.

• A focusable area is said to be click focusable if the user agent determines that it is click focusable. User agents should consider focusable areas with non-null tabindex values to be click focusable.

Elements which are not focusable are not focusable areas, and thus not sequentially focusable and not click focusable.

If the activation behavior of a click focusable focusable area is triggered, the user agent must run the focusing steps on the focusable area's DOM anchor.

A node is a focus navigation scope owner if it is a document, a shadow host or a slot.

Each focus navigation scope owner has a focus navigation scope, which is a list of elements. Its contents are determined as follows:

Every element element has an associated focus navigation owner, which is either null or a focus navigation scope owner. It is determined by the following algorithm:

1. If element's parent is null, then return null.

2. If element's parent is a shadow host, then return element's assigned slot.

3. If element's parent is a shadow root, then return the parent's host.

4. If element's parent is the document element, then return the parent's node document.

5. Return element's parent's associated focus navigation owner.

Then, the contents of a given focus navigation scope owner owner's focus navigation scope are all elements whose associated focus navigation owner is owner.

The order of elements within a focus navigation scope does not impact any of the algorithms in this specification. Ordering only becomes important for the tabindex-ordered focus navigation scope and flattened tabindex-ordered focus navigation scope concepts defined below.

A tabindex-ordered focus navigation scope is a list of focusable areas and focus navigation scope owners. Every focus navigation scope owner owner has tabindex-ordered focus navigation scope, whose contents are determined as follows:

• It contains all elements in owner's focus navigation scope that are themselves focus navigation scope owners, except the elements whose tabindex value is a negative integer.

• It contains all of the focusable areas whose DOM anchor is an element in owner's focus navigation scope, except the focusable areas whose tabindex value is a negative integer.

The order within a tabindex-ordered focus navigation scope is determined by each element's tabindex value, as described in the section below.

The rules there do not give a precise ordering, as they are composed mostly of "should" statements and relative orderings.

A flattened tabindex-ordered focus navigation scope is a list of focusable areas. Every focus navigation scope owner owner owns a distinct flattened tabindex-ordered focus navigation scope, whose contents are determined by the following algorithm:

1. Let result be a clone of owner's tabindex-ordered focus navigation scope.

2. For each item of result:

   1. If item is not a focus navigation scope owner, then continue.

   2. If item is not a focusable area, then replace item with all of the items in item's flattened tabindex-ordered focus navigation scope.

   3. Otherwise, insert the contents of item's flattened tabindex-ordered focus navigation scope after item.

6.5.3 The tabindex attribute

The tabindex content attribute allows authors to make an element and regions that have the element as its DOM anchor be focusable areas, allow or prevent them from being sequentially focusable, and determine their relative ordering for sequential focus navigation.

The name "tab index" comes from the common use of the Tab key to navigate through the focusable elements. The term "tabbing" refers to moving forward through sequentially focusable focusable areas.

The tabindex attribute, if specified, must have a value that is a valid integer. Positive numbers specify the relative position of the element's focusable areas in the sequential focus navigation order, and negative numbers indicate that the control is not sequentially focusable.

Developers should use caution when using values other than 0 or −1 for their tabindex attributes as this is complicated to do correctly.

An element with the tabindex attribute specified is interactive content.

The tabindex value of an element is the value of its tabindex attribute, parsed using the rules for parsing integers. If parsing fails or the attribute is not specified, then the tabindex value is null.

The tabindex value of a focusable area is the tabindex value of its DOM anchor.

The tabindex value of an element must be interpreted as follows:

If the value is null

The user agent should follow platform conventions to determine if the element should be considered as a focusable area and if so, whether the element and any focusable areas that have the element as their DOM anchor are sequentially focusable, and if so, what their relative position in their tabindex-ordered focus navigation scope is to be. If the element is a focus navigation scope owner, it must be included in its tabindex-ordered focus navigation scope even if it is not a focusable area.

The relative ordering within a tabindex-ordered focus navigation scope for elements and focusable areas that belong to the same focus navigation scope and whose tabindex value is null should be in shadow-including tree order.

Modulo platform conventions, it is suggested that the following elements should be considered as focusable areas:

• a elements that have an href attribute
• link elements that have an href attribute
• button elements
• input elements whose type attribute are not in the Hidden state
• select elements
• textarea elements
• summary elements that are the first summary element child of a details element
• Elements with a draggable attribute set, if that would enable the user agent to allow the user to begin a drag operations for those elements without the use of a pointing device
• Editing hosts
• Browsing context containers

If the value is a negative integer

The user agent must consider the element as a focusable area, but should omit the element from any tabindex-ordered focus navigation scope.

One valid reason to ignore the requirement that sequential focus navigation not allow the author to lead to the element would be if the user's only mechanism for moving the focus is sequential focus navigation. For instance, a keyboard-only user would be unable to click on a text control with a negative tabindex, so that user's user agent would be well justified in allowing the user to tab to the control regardless.

If the value is a zero

The user agent must allow the element to be considered as a focusable area and should allow the element and any focusable areas that have the element as their DOM anchor to be sequentially focusable.

The relative ordering within a tabindex-ordered focus navigation scope for elements and focusable areas that belong to the same focus navigation scope and whose tabindex value is zero should be in shadow-including tree order.

If the value is greater than zero

The user agent must allow the element to be considered as a focusable area and should allow the element and any focusable areas that have the element as their DOM anchor to be sequentially focusable, and should place the element — referenced as candidate below — and the aforementioned focusable areas in the tabindex-ordered focus navigation scope where the element is a part of so that, relative to other elements and focusable areas that belong to the same focus navigation scope, they are:

• before any focusable area whose DOM anchor is an element whose tabindex attribute has been omitted or whose value, when parsed, returns an error,
• before any focusable area whose DOM anchor is an element whose tabindex attribute has a value equal to or less than zero,
• after any focusable area whose DOM anchor is an element whose tabindex attribute has a value greater than zero but less than the value of the tabindex attribute on candidate,
• after any focusable area whose DOM anchor is an element whose tabindex attribute has a value equal to the value of the tabindex attribute on candidate but that is located earlier than candidate in shadow-including tree order,
• before any focusable area whose DOM anchor is an element whose tabindex attribute has a value equal to the value of the tabindex attribute on candidate but that is located later than candidate in shadow-including tree order, and
• before any focusable area whose DOM anchor is an element whose tabindex attribute has a value greater than the value of the tabindex attribute on candidate.

The tabIndex IDL attribute must reflect the value of the tabindex content attribute. The default value is 0 if the element is an a, area, button, frame, iframe, input, object, select, textarea, or SVG a element, or is a summary element that is a summary for its parent details. The default value is −1 otherwise.

The varying default value based on element type is a historical artifact.

6.5.4 Processing model

The focusing steps for an object new focus target that is either a focusable area, or an element that is not a focusable area, or a browsing context, are as follows. They can optionally be run with a fallback target.

1. If new focus target is not a focusable area, then run the first matching set of steps from the following list:

   If new focus target is an area element with one or more shapes that are focusable areas

   Let new focus target be the shape corresponding to the first img element in tree order that uses the image map to which the area element belongs.

   If new focus target is an element with one or more scrollable regions that are focusable areas

   Let new focus target be the element's first scrollable region, according to a pre-order, depth-first traversal of the box tree. [CSS]

   If new focus target is the document element of its Document

   Let new focus target be the Document's viewport.

   If new focus target is a browsing context

   Let new focus target be the browsing context's active document.

   If new focus target is a browsing context container with a non-null nested browsing context

   Let new focus target be the browsing context container's nested browsing context's active document.

   Otherwise

   If no fallback target was specified, abort the focusing steps.

   Otherwise, let new focus target be the fallback target.

2. If new focus target is a browsing context container with non-null nested browsing context, then let new focus target be the nested browsing context's active document, and redo this step.

3. If new focus target is a focusable area and its DOM anchor is inert, then return.

4. If new focus target is the currently focused area of a top-level browsing context, then return.

5. Let old chain be the focus chain of the currently focused area of the top-level browsing context in which new focus target finds itself.

6. Let new chain be the focus chain of new focus target.

7. Run the focus update steps with old chain, new chain, and new focus target respectively.

User agents must immediately run the focusing steps for a focusable area or browsing context candidate whenever the user attempts to move the focus to candidate.

The unfocusing steps for an object old focus target that is either a focusable area or an element that is not a focusable area are as follows:

1. If old focus target is inert, then return.

2. If old focus target is an area element and one of its shapes is the currently focused area of a top-level browsing context, or, if old focus target is an element with one or more scrollable regions, and one of them is the currently focused area of a top-level browsing context, then let old focus target be that currently focused area of a top-level browsing context.

3. Let old chain be the focus chain of the currently focused area of a top-level browsing context.

4. If old focus target is not one of the entries in old chain, then return.

5. If old focus target is a focusable area, then let new focus target be its Document's viewport.

   Otherwise, let new focus target be null.

6. If new focus target is not null, then run the focusing steps for new focus target.

When the currently focused area of a top-level browsing context is somehow unfocused without another element being explicitly focused in its stead, the user agent must immediately run the unfocusing steps for that object.

The unfocusing steps do not always result in the focus changing, even when applied to the currently focused area of a top-level browsing context. For example, if the currently focused area of a top-level browsing context is a viewport, then it will usually keep its focus regardless until another focusable area is explicitly focused with the focusing steps.

Focus fixup rule: When the designated focused area of the document is removed from that Document in some way (e.g. it stops being a focusable area, it is removed from the DOM, it becomes expressly inert, etc.), designate the Document's viewport to be the new focused area of the document.

For example, this might happen because an element is removed from its Document, or has a hidden attribute added. It might also happen to an input element when the element gets disabled.

In a Document whose focused area is a button element, removing, disabling, or hiding that button would cause the page's new focused area to be the viewport of the Document. This would, in turn, be reflected through the activeElement API as the body element.

The focus update steps, given an old chain, a new chain, and a new focus target respectively, are as follows:

1. If the last entry in old chain and the last entry in new chain are the same, pop the last entry from old chain and the last entry from new chain and redo this step.

2. For each entry entry in old chain, in order, run these substeps:

   1. If entry is an input element, and the change event applies to the element, and the element does not have a defined activation behavior, and the user has changed the element's value or its list of selected files while the control was focused without committing that change (such that it is different to what it was when the control was first focused), then fire an event named change at the element, with the bubbles attribute initialized to true.

   2. If entry is an element, let blur event target be entry.

      If entry is a Document object, let blur event target be that Document object's relevant global object.

      Otherwise, let blur event target be null.

   3. If entry is the last entry in old chain, and entry is an Element, and the last entry in new chain is also an Element, then let related blur target be the last entry in new chain. Otherwise, let related blur target be null.

   4. If blur event target is not null, fire a focus event named blur at blur event target, with related blur target as the related target.

      In some cases, e.g. if entry is an area element's shape, a scrollable region, or a viewport, no event is fired.

3. Apply any relevant platform-specific conventions for focusing new focus target. (For example, some platforms select the contents of a text control when that control is focused.)

4. For each entry entry in new chain, in reverse order, run these substeps:

   1. If entry is a focusable area: designate entry as the focused area of the document.

   2. If entry is an element, let focus event target be entry.

      If entry is a Document object, let focus event target be that Document object's relevant global object.

      Otherwise, let focus event target be null.

   3. If entry is the last entry in new chain, and entry is an Element, and the last entry in old chain is also an Element, then let related focus target be the last entry in old chain. Otherwise, let related focus target be null.

   4. If focus event target is not null, fire a focus event named focus at focus event target, with related focus target as the related target.

      In some cases, e.g. if entry is an area element's shape, a scrollable region, or a viewport, no event is fired.

To fire a focus event named e at an element t with a given related target r, fire an event named e at t, using FocusEvent, with the relatedTarget attribute initialized to r, the view attribute initialized to t's node document's relevant global object, and the composed flag set.

When a key event is to be routed in a top-level browsing context, the user agent must run the following steps:

1. Let target area be the currently focused area of the top-level browsing context.

2. If target area is a focusable area, let target node be target area's DOM anchor. Otherwise, target area is a dialog; let target node be target area.

3. If target node is a Document that has a body element, then let target node be the body element of that Document.

   Otherwise, if target node is a Document object that has a non-null document element, then let target node be that document element.

4. If target node is not inert, then:

   It is possible for the currently focused area of a top-level browsing context to be inert, for example if a modal dialog is shown, and then that dialog element is made inert. It is likely to be the result of a logic error in the application, though.

   1. Let canHandle be the result of dispatching the key event at target node.

   2. If canHandle is true, then let target area handle the key event. This might include firing a click event at target node.

The has focus steps, given a Document object target, are as follows:

1. Let candidate be the Document of the top-level browsing context.

2. While true:

   1. If candidate is target, then return true.

   2. If the focused area of candidate is a browsing context container with a non-null nested browsing context, then set candidate to the active document of that browsing context container's nested browsing context.

   3. Otherwise, return false.

6.5.5 Sequential focus navigation

Each Document has a sequential focus navigation order, which orders some or all of the focusable areas in the Document relative to each other. Its contents and ordering are given by the flattened tabindex-ordered focus navigation scope of the Document.

Per the rules defining the flattened tabindex-ordered focus navigation scope, the ordering is not necessarily related to the tree order of the Document.

If a focusable area is omitted from the sequential focus navigation order of its Document, then it is unreachable via sequential focus navigation.

There can also be a sequential focus navigation starting point. It is initially unset. The user agent may set it when the user indicates that it should be moved.

For example, the user agent could set it to the position of the user's click if the user clicks on the document contents.

When the user requests that focus move from the currently focused area of a top-level browsing context to the next or previous focusable area (e.g. as the default action of pressing the tab key), or when the user requests that focus sequentially move to a top-level browsing context in the first place (e.g. from the browser's location bar), the user agent must use the following algorithm:

1. Let starting point be the currently focused area of a top-level browsing context, if the user requested to move focus sequentially from there, or else the top-level browsing context itself, if the user instead requested to move focus from outside the top-level browsing context.

2. If there is a sequential focus navigation starting point defined and it is inside starting point, then let starting point be the sequential focus navigation starting point instead.

3. Let direction be forward if the user requested the next control, and backward if the user requested the previous control.

   Typically, pressing tab requests the next control, and pressing shift+tab requests the previous control.

4. Loop: Let selection mechanism be sequential if the starting point is a browsing context or if starting point is in its Document's sequential focus navigation order.

   Otherwise, starting point is not in its Document's sequential focus navigation order; let selection mechanism be DOM.

5. Let candidate be the result of running the sequential navigation search algorithm with starting point, direction, and selection mechanism as the arguments.

6. If candidate is not null, then run the focusing steps for candidate and return.

7. Otherwise, unset the sequential focus navigation starting point.

8. If starting point is the top-level browsing context, or a focusable area in the top-level browsing context, the user agent should transfer focus to its own controls appropriately (if any), honouring direction, and then return.

   For example, if direction is backward, then the last sequentially focusable control before the browser's rendering area would be the control to focus.

   If the user agent has no sequentially focusable controls — a kiosk-mode browser, for instance — then the user agent may instead restart these steps with the starting point being the top-level browsing context itself.

9. Otherwise, starting point is a focusable area in a nested browsing context. Let starting point be that nested browsing context's browsing context container, and return to the step labeled loop.

The sequential navigation search algorithm consists of the following steps. This algorithm takes three arguments: starting point, direction, and selection mechanism.

1. Pick the appropriate cell from the following table, and follow the instructions in that cell.

   The appropriate cell is the one that is from the column whose header describes direction and from the first row whose header describes starting point and selection mechanism.

   	direction is forward	direction is backward
   starting point is a browsing context	Let candidate be the first suitable sequentially focusable area in starting point's active document, if any; or else null	Let candidate be the last suitable sequentially focusable area in starting point's active document, if any; or else null
   selection mechanism is DOM	Let candidate be the first suitable sequentially focusable area in the home document following starting point, if any; or else null	Let candidate be the last suitable sequentially focusable area in the home document preceding starting point, if any; or else null
   selection mechanism is sequential	Let candidate be the first suitable sequentially focusable area in the home sequential focus navigation order following starting point, if any; or else null	Let candidate be the last suitable sequentially focusable area in the home sequential focus navigation order preceding starting point, if any; or else null

   A suitable sequentially focusable area is a focusable area whose DOM anchor is not inert and is sequentially focusable.

   The home document is the Document to which starting point belongs.

   The home sequential focus navigation order is the sequential focus navigation order to which starting point belongs.

   The home sequential focus navigation order is the home document's sequential focus navigation order, but is only used when the starting point is in that sequential focus navigation order (when it's not, selection mechanism will be DOM).

2. If candidate is a browsing context container with a non-null nested browsing context, then let new candidate be the result of running the sequential navigation search algorithm with candidate's nested browsing context as the first argument, direction as the second, and sequential as the third.

   If new candidate is null, then let starting point be candidate, and return to the top of this algorithm. Otherwise, let candidate be new candidate.

3. Return candidate.

6.5.6 Focus management APIs

dictionary FocusOptions {
  boolean preventScroll = false;
};

documentOrShadowRoot . activeElement

Returns the deepest element in the document through which or to which key events are being routed. This is, roughly speaking, the focused element in the document.

For the purposes of this API, when a child browsing context is focused, its browsing context container is focused in the parent browsing context. For example, if the user moves the focus to a text control in an iframe, the iframe is the element returned by the activeElement API in the iframe's node document.

Similarly, when the focused element is in a different node tree than documentOrShadowRoot, the element returned will be the host that's located in the same node tree as documentOrShadowRoot if documentOrShadowRoot is a shadow-including inclusive ancestor of the focused element, and null if not.

document . hasFocus()

Returns true if key events are being routed through or to the document; otherwise, returns false. Roughly speaking, this corresponds to the document, or a document nested inside this one, being focused.

window . focus()

Moves the focus to the window's browsing context, if any.

element . focus([ { preventScroll: true } ])

Moves the focus to the element.

If the element is a browsing context container, moves the focus to the nested browsing context instead.

By default, this method also scrolls the element into view. Providing the preventScroll option and setting it to true prevents this behavior.

element . blur()

Moves the focus to the viewport. Use of this method is discouraged; if you want to focus the viewport, call the focus() method on the Document's document element.

Do not use this method to hide the focus ring if you find the focus ring unsightly. Instead, use a CSS rule to override the 'outline' property, and provide a different way to show what element is focused. Be aware that if an alternative focusing style isn't made available, the page will be significantly less usable for people who primarily navigate pages using a keyboard, or those with reduced vision who use focus outlines to help them navigate the page.

For example, to hide the outline from links and instead use a yellow background to indicate focus, you could use:

:link:focus, :visited:focus { outline: none; background: yellow; color: black; }

The activeElement attribute's getter must run these steps:

1. Let candidate be the DOM anchor of the focused area of this DocumentOrShadowRoot's node document.

2. Set candidate to the result of retargeting candidate against this DocumentOrShadowRoot.

3. If candidate's root is not this DocumentOrShadowRoot, then return null.

4. If candidate is not a Document object, then return candidate.

5. If candidate has a body element, then return that body element.

6. If candidate's document element is non-null, then return that document element.

7. Return null.

The hasFocus() method on the Document object, when invoked, must return the result of running the has focus steps with the Document object as the argument.

The focus() method, when invoked, must run these steps:

1. Let current be this Window object's browsing context.

2. If current is null, then return.

3. Run the focusing steps with current.

4. If current is a top-level browsing context, user agents are encouraged to trigger some sort of notification to indicate to the user that the page is attempting to gain focus.

The blur() method, when invoked, provides a hint to the user agent that the script believes the user probably is not currently interested in the contents of this Window object's browsing context, if non-null, but that the contents might become interesting again in the future.

User agents are encouraged to ignore calls to this blur() method entirely.

Historically, the focus() and blur() methods actually affected the system-level focus of the system widget (e.g., tab or window) that contained the browsing context, but hostile sites widely abuse this behavior to the user's detriment.

The focus(options) method on elements, when invoked, must run the following steps:

1. If the element is marked as locked for focus, then return.

2. Mark the element as locked for focus.

3. Run the focusing steps for the element.

4. If the value of the preventScroll dictionary member of options is false, then scroll the element into view with scroll behavior "auto", block flow direction position set to a UA-defined value, and inline base direction position set to a UA-defined value.

5. Unmark the element as locked for focus.

The blur() method, when invoked, should run the unfocusing steps for the element on which the method was called. User agents may selectively or uniformly ignore calls to this method for usability reasons.

For example, if the blur() method is unwisely being used to remove the focus ring for aesthetics reasons, the page would become unusable by keyboard users. Ignoring calls to this method would thus allow keyboard users to interact with the page.

6.5.7 The autofocus attribute

The autofocus content attribute allows the author to indicate that an element is to be focused as soon as the page is loaded or as soon as the dialog within which it finds itself is shown, allowing the user to just start typing without having to manually focus the main element.

The autofocus attribute is a boolean attribute.

An element's nearest ancestor autofocus scoping root element is the element itself if the element is a dialog element, or else is the element's nearest ancestor dialog element, if any, or else is the element's last inclusive ancestor element.

There must not be two elements with the same nearest ancestor autofocus scoping root element that both have the autofocus attribute specified.

Each Document has an autofocus candidates list, initially empty.

Each Document has an autofocus processed flag boolean, initially false.

When an element with the autofocus attribute specified is inserted into a document, run the following steps:

1. If the user has indicated (for example, by starting to type in a form control) that they do not wish focus to be changed, then optionally return.

2. Let target be the element's node document.

3. If target's browsing context is null, then return.

4. If target's active sandboxing flag set has the sandboxed automatic features browsing context flag, then return.

5. Let topDocument be the active document of target's browsing context's top-level browsing context.

6. If target's origin is not the same as the origin of topDocument, then return.

7. If topDocument's autofocus processed flag is false, then remove the element from topDocument's autofocus candidates, and append the element to topDocument's autofocus candidates.

We do not check if an element is a focusable area before storing it in the autofocus candidates list, because even if it is not a focusable area when it is inserted, it could become one by the time flush autofocus candidates sees it.

To flush autofocus candidates for a document topDocument, run these steps:

1. If topDocument's autofocus processed flag is true, then return.

2. Let candidates be topDocument's autofocus candidates.

3. If candidates is empty, then return.

4. If topDocument's focused area is not topDocument itself, or topDocument's URL's fragment is not empty, then:

   1. Empty candidates.

   2. Set topDocument's autofocus processed flag to true.

   3. Return.

5. While candidates is not empty:

   1. Let element be candidates[0].

   2. Let doc be element's node document.

   3. If doc is not fully active, then remove element from candidates, and continue.

   4. If doc's browsing context's top-level browsing context is not same as topDocument's browsing context, then remove element from candidates, and continue.

   5. If doc's script-blocking style sheet counter is greater than 0, then return.

      In this case, element is the currently-best candidate, but doc is not ready for autofocusing. We'll try again next time flush autofocus candidates is called.

   6. Remove element from candidates.

   7. Let inclusiveAncestorDocuments be a list consisting of doc, plus the active documents of each of doc's browsing context's ancestor browsing contexts.

   8. If URL's fragment of any Document in inclusiveAncestorDocuments is not empty, then continue.

   9. If element is a focusable area, then:

      1. Empty candidates.

      2. Set topDocument's autofocus processed flag to true.

      3. Run the focusing steps for element.

      Autofocus candidates can contain elements which are not focusable areas. This can happen either because a non-focusable area element with an autofocus attribute was inserted into a document and it never became focusable, or because the element was focusable but its status changed while it was stored in autofocus candidates.

This handles the automatic focusing during document load. The show() and showModal() methods of dialog elements also processes the autofocus attribute.

Focusing the element does not imply that the user agent has to focus the browser window if it has lost focus.

The autofocus IDL attribute must reflect the content attribute of the same name.

<input maxlength="256" name="q" value="" autofocus>
<input type="submit" value="Search">

<div contenteditable autofocus>Edit <strong>me!</strong><div>

6.6 Assigning keyboard shortcuts

6.6.1 Introduction

This section is non-normative.

Each element that can be activated or focused can be assigned a single key combination to activate it, using the accesskey attribute.

The exact shortcut is determined by the user agent, based on information about the user's keyboard, what keyboard shortcuts already exist on the platform, and what other shortcuts have been specified on the page, using the information provided in the accesskey attribute as a guide.

In order to ensure that a relevant keyboard shortcut is available on a wide variety of input devices, the author can provide a number of alternatives in the accesskey attribute.

Each alternative consists of a single character, such as a letter or digit.

User agents can provide users with a list of the keyboard shortcuts, but authors are encouraged to do so also. The accessKeyLabel IDL attribute returns a string representing the actual key combination assigned by the user agent.

<input type=button value=Collect onclick="collect()"
       accesskey="C 1" id=c>

function addShortcutKeyLabel(button) {
  if (button.accessKeyLabel != '')
    button.value += ' (' + button.accessKeyLabel + ')';
}
addShortcutKeyLabel(document.getElementById('c'));

6.6.2 The accesskey attribute

All HTML elements may have the accesskey content attribute set. The accesskey attribute's value is used by the user agent as a guide for creating a keyboard shortcut that activates or focuses the element.

If specified, the value must be an ordered set of unique space-separated tokens that are case-sensitive, each of which must be exactly one code point in length.

<nav>
 <p>
  <a title="Consortium Activities" accesskey="A" href="/Consortium/activities">Activities</a> |
  <a title="Technical Reports and Recommendations" accesskey="T" href="/TR/">Technical Reports</a> |
  <a title="Alphabetical Site Index" accesskey="S" href="/Consortium/siteindex">Site Index</a> |
  <a title="About This Site" accesskey="B" href="/Consortium/">About Consortium</a> |
  <a title="Contact Consortium" accesskey="C" href="/Consortium/contact">Contact</a>
 </p>
</nav>

<form action="/search">
 <label>Search: <input type="search" name="q" accesskey="s 0"></label>
 <input type="submit">
</form>

<input type=submit accesskey="N @ 1" value="Compose">
...
<script>
 function labelButton(button) {
   if (button.accessKeyLabel)
     button.value += ' (' + button.accessKeyLabel + ')';
 }
 var inputs = document.getElementsByTagName('input');
 for (var i = 0; i < inputs.length; i += 1) {
   if (inputs[i].type == "submit")
     labelButton(inputs[i]);
 }
</script>

6.6.3 Processing model

An element's assigned access key is a key combination derived from the element's accesskey content attribute. Initially, an element must not have an assigned access key.

Whenever an element's accesskey attribute is set, changed, or removed, the user agent must update the element's assigned access key by running the following steps:

1. If the element has no accesskey attribute, then skip to the fallback step below.

2. Otherwise, split the attribute's value on ASCII whitespace, and let keys be the resulting tokens.

3. For each value in keys in turn, in the order the tokens appeared in the attribute's value, run the following substeps:

   1. If the value is not a string exactly one code point in length, then skip the remainder of these steps for this value.

   2. If the value does not correspond to a key on the system's keyboard, then skip the remainder of these steps for this value.

   3. If the user agent can find a mix of zero or more modifier keys that, combined with the key that corresponds to the value given in the attribute, can be used as the access key, then the user agent may assign that combination of keys as the element's assigned access key and return.

4. Fallback: Optionally, the user agent may assign a key combination of its choosing as the element's assigned access key and then return.

5. If this step is reached, the element has no assigned access key.

Once a user agent has selected and assigned an access key for an element, the user agent should not change the element's assigned access key unless the accesskey content attribute is changed or the element is moved to another Document.

When the user presses the key combination corresponding to the assigned access key for an element, if the element defines a command, the command's Hidden State facet is false (visible), the command's Disabled State facet is also false (enabled), the element is in a document that has a non-null browsing context, and neither the element nor any of its ancestors has a hidden attribute specified, then the user agent must trigger the Action of the command.

User agents might expose elements that have an accesskey attribute in other ways as well, e.g. in a menu displayed in response to a specific key combination.

The accessKey IDL attribute must reflect the accesskey content attribute.

The accessKeyLabel IDL attribute must return a string that represents the element's assigned access key, if any. If the element does not have one, then the IDL attribute must return the empty string.

6.7 Editing

6.7.1 Making document regions editable: The contenteditable content attribute

interface mixin ElementContentEditable {
  [CEReactions] attribute DOMString contentEditable;
  [CEReactions] attribute DOMString enterKeyHint;
  readonly attribute boolean isContentEditable;
  [CEReactions] attribute DOMString inputMode;
};

The contenteditable content attribute is an enumerated attribute whose keywords are the empty string, true, and false. The empty string and the true keyword map to the true state. The false keyword maps to the false state. In addition, there is a third state, the inherit state, which is the missing value default and the invalid value default.

The true state indicates that the element is editable. The inherit state indicates that the element is editable if its parent is. The false state indicates that the element is not editable.

<form method=POST>
 <fieldset>
  <legend>New article</legend>
  <textarea name=article>&lt;p>Hello world.&lt;/p></textarea>
 </fieldset>
 <p><button>Publish</button></p>
</form>

<form method=POST>
 <fieldset>
  <legend>New article</legend>
  <textarea id=textarea name=article>&lt;p>Hello world.&lt;/p></textarea>
  <div id=div style="white-space: pre-wrap" hidden><p>Hello world.</p></div>
  <script>
   let textarea = document.getElementById("textarea");
   let div = document.getElementById("div");
   textarea.hidden = true;
   div.hidden = false;
   div.contentEditable = "true";
   div.oninput = (e) => {
     textarea.value = div.innerHTML;
   };
  </script>
 </fieldset>
 <p><button>Publish</button></p>
</form>

<!doctype html>
<html lang=en>
<title>Live CSS editing!</title>
<style style=white-space:pre contenteditable>
html { margin:.2em; font-size:2em; color:lime; background:purple }
head, title, style { display:block }
body { display:none }
</style>

element . contentEditable [ = value ]

Returns "true", "false", or "inherit", based on the state of the contenteditable attribute.

Can be set, to change that state.

Throws a "SyntaxError" DOMException if the new value isn't one of those strings.

element . isContentEditable

Returns true if the element is editable; otherwise, returns false.

The contentEditable IDL attribute, on getting, must return the string "true" if the content attribute is set to the true state, "false" if the content attribute is set to the false state, and "inherit" otherwise. On setting, if the new value is an ASCII case-insensitive match for the string "inherit" then the content attribute must be removed, if the new value is an ASCII case-insensitive match for the string "true" then the content attribute must be set to the string "true", if the new value is an ASCII case-insensitive match for the string "false" then the content attribute must be set to the string "false", and otherwise the attribute setter must throw a "SyntaxError" DOMException.

The isContentEditable IDL attribute, on getting, must return true if the element is either an editing host or editable, and false otherwise.

6.7.2 Making entire documents editable: the designMode IDL attribute

Documents have a designMode, which can be either enabled or disabled.

document . designMode [ = value ]

Returns "on" if the document is editable, and "off" if it isn't.

Can be set, to change the document's current state. This focuses the document and resets the selection in that document.

The designMode IDL attribute on the Document object takes two values, "on" and "off". On setting, the new value must be compared in an ASCII case-insensitive manner to these two values; if it matches the "on" value, then designMode must be enabled, and if it matches the "off" value, then designMode must be disabled. Other values must be ignored.

On getting, if designMode is enabled, the IDL attribute must return the value "on"; otherwise it is disabled, and the attribute must return the value "off".

The last state set must persist until the document is destroyed or the state is changed. Initially, documents must have their designMode disabled.

When the designMode changes from being disabled to being enabled, the user agent must immediately reset the document's active range's start and end boundary points to be at the start of the Document and then run the focusing steps for the document element of the Document, if non-null.

6.7.3 Best practices for in-page editors

Authors are encouraged to set the 'white-space' property on editing hosts and on markup that was originally created through these editing mechanisms to the value 'pre-wrap'. Default HTML whitespace handling is not well suited to WYSIWYG editing, and line wrapping will not work correctly in some corner cases if 'white-space' is left at its default value.

6.7.4 Editing APIs

The definition of the terms active range, editing host, editing host of, and editable, the user interface requirements of elements that are editing hosts or editable, the execCommand(), queryCommandEnabled(), queryCommandIndeterm(), queryCommandState(), queryCommandSupported(), and queryCommandValue() methods, text selections, and the delete the selection algorithm are defined in execCommand. [EXECCOMMAND]

6.7.5 Spelling and grammar checking

User agents can support the checking of spelling and grammar of editable text, either in form controls (such as the value of textarea elements), or in elements in an editing host (e.g. using contenteditable).

For each element, user agents must establish a default behavior, either through defaults or through preferences expressed by the user. There are three possible default behaviors for each element:

true-by-default

The element will be checked for spelling and grammar if its contents are editable and spellchecking is not explicitly disabled through the spellcheck attribute.

false-by-default

The element will never be checked for spelling and grammar unless spellchecking is explicitly enabled through the spellcheck attribute.

inherit-by-default

The element's default behavior is the same as its parent element's. Elements that have no parent element cannot have this as their default behavior.

The spellcheck attribute is an enumerated attribute whose keywords are the empty string, true and false. The empty string and the true keyword map to the true state. The false keyword maps to the false state. In addition, there is a third state, the default state, which is the missing value default and the invalid value default.

The true state indicates that the element is to have its spelling and grammar checked. The default state indicates that the element is to act according to a default behavior, possibly based on the parent element's own spellcheck state, as defined below. The false state indicates that the element is not to be checked.

element . spellcheck [ = value ]

Returns true if the element is to have its spelling and grammar checked; otherwise, returns false.

Can be set, to override the default and set the spellcheck content attribute.

The spellcheck IDL attribute, on getting, must return true if the element's spellcheck content attribute is in the true state, or if the element's spellcheck content attribute is in the default state and the element's default behavior is true-by-default, or if the element's spellcheck content attribute is in the default state and the element's default behavior is inherit-by-default and the element's parent element's spellcheck IDL attribute would return true; otherwise, if none of those conditions applies, then the attribute must instead return false.

The spellcheck IDL attribute is not affected by user preferences that override the spellcheck content attribute, and therefore might not reflect the actual spellchecking state.

On setting, if the new value is true, then the element's spellcheck content attribute must be set to the literal string "true", otherwise it must be set to the literal string "false".

User agents must only consider the following pieces of text as checkable for the purposes of this feature:

• The value of input elements whose type attributes are in the Text, Search, URL, or E-mail states and that are mutable (i.e. that do not have the readonly attribute specified and that are not disabled).
• The value of textarea elements that do not have a readonly attribute and that are not disabled.
• Text in Text nodes that are children of editing hosts or editable elements.
• Text in attributes of editable elements.

For text that is part of a Text node, the element with which the text is associated is the element that is the immediate parent of the first character of the word, sentence, or other piece of text. For text in attributes, it is the attribute's element. For the values of input and textarea elements, it is the element itself.

To determine if a word, sentence, or other piece of text in an applicable element (as defined above) is to have spelling- and grammar-checking enabled, the UA must use the following algorithm:

1. If the user has disabled the checking for this text, then the checking is disabled.
2. Otherwise, if the user has forced the checking for this text to always be enabled, then the checking is enabled.
3. Otherwise, if the element with which the text is associated has a spellcheck content attribute, then: if that attribute is in the true state, then checking is enabled; otherwise, if that attribute is in the false state, then checking is disabled.
4. Otherwise, if there is an ancestor element with a spellcheck content attribute that is not in the default state, then: if the nearest such ancestor's spellcheck content attribute is in the true state, then checking is enabled; otherwise, checking is disabled.
5. Otherwise, if the element's default behavior is true-by-default, then checking is enabled.
6. Otherwise, if the element's default behavior is false-by-default, then checking is disabled.
7. Otherwise, if the element's parent element has its checking enabled, then checking is enabled.
8. Otherwise, checking is disabled.

If the checking is enabled for a word/sentence/text, the user agent should indicate spelling and grammar errors in that text. User agents should take into account the other semantics given in the document when suggesting spelling and grammar corrections. User agents may use the language of the element to determine what spelling and grammar rules to use, or may use the user's preferred language settings. UAs should use input element attributes such as pattern to ensure that the resulting value is valid, where possible.

If checking is disabled, the user agent should not indicate spelling or grammar errors for that text.

<div contenteditable="true">
 <span spellcheck="false" id="a">Hell</span><em>o!</em>
</div>

<p spellcheck="true">
 <label>Name: <input spellcheck=" false" id="b"></label>
</p>

This specification does not define the user interface for spelling and grammar checkers. A user agent could offer on-demand checking, could perform continuous checking while the checking is enabled, or could use other interfaces.

6.7.6 Autocapitalization

Some methods of entering text, for example virtual keyboards on mobile devices, and also voice input, often assist users by automatically capitalizing the first letter of sentences (when composing text in a language with this convention). A virtual keyboard that implements autocapitalization might automatically switch to showing uppercase letters (but allow the user to toggle it back to lowercase) when a letter that should be autocapitalized is about to be typed. Other types of input, for example voice input, may perform autocapitalization in a way that does not give users an option to intervene first. The autocapitalize attribute allows authors to control such behavior.

The autocapitalize attribute, as typically implemented, does not affect behavior when typing on a physical keyboard. (For this reason, as well as the ability for users to override the autocapitalization behavior in some cases or edit the text after initial input, the attribute must not be relied on for any sort of input validation.)

The autocapitalize attribute can be used on an editing host to control autocapitalization behavior for the hosted editable region, on an input or textarea element to control the behavior for inputting text into that element, or on a form element to control the default behavior for all autocapitalize-inheriting elements associated with the form element.

The autocapitalize attribute never causes autocapitalization to be enabled for input elements whose type attribute is in one of the URL, E-mail, or Password states. (This behavior is included in the used autocapitalization hint algorithm below.)

The autocapitalization processing model is based on selecting among five autocapitalization hints, defined as follows:

default

The user agent and input method should use make their own determination of whether or not to enable autocapitalization.

none

No autocapitalization should be applied (all letters should default to lowercase).

sentences

The first letter of each sentence should default to a capital letter; all other letters should default to lowercase.

words

The first letter of each word should default to a capital letter; all other letters should default to lowercase.

characters

All letters should default to uppercase.

The autocapitalize attribute is an enumerated attribute whose states are the possible autocapitalization hints. The autocapitalization hint specified by the attribute's state combines with other considerations to form the used autocapitalization hint, which informs the behavior of the user agent. The keywords for this attribute and their state mappings are as follows:

The invalid value default is the sentences state. The missing value default is the default state.

element . autocapitalize [ = value ]

Returns the current autocapitalization state for the element, or an empty string if it hasn't been set. Note that for input and textarea elements that inherit their state from a form element, this will return the autocapitalization state of the form element, but for an element in an editable region, this will not return the autocapitalization state of the editing host (unless this element is, in fact, the editing host).

Can be set, to set the autocapitalize content attribute (and thereby change the autocapitalization behavior for the element).

To compute the own autocapitalization hint of an element element, run the following steps:

1. If the autocapitalize content attribute is present on element, and its value is not the empty string, return the state of the attribute.

2. If element is an autocapitalize-inheriting element and has a non-null form owner, return the own autocapitalization hint of element's form owner.

3. Return default.

The autocapitalize IDL attribute, on getting, must return the string value corresponding to own autocapitalization hint of the element, with the exception that the default state maps to the empty string. On setting, it must set the autocapitalize content attribute to the given new value.

User agents that support customizable autocapitalization behavior for a text input method and wish to allow web developers to control this functionality should, during text input into an element, compute the used autocapitalization hint for the element. This will be an autocapitalization hint that describes the recommended autocapitalization behavior for text input into the element.

User agents or input methods may choose to ignore or override the used autocapitalization hint in certain circumstances.

The used autocapitalization hint for an element element is computed using the following algorithm:

1. If element is an input element whose type attribute is in one of the URL, E-mail, or Password states, then return default.

2. If element is an input element or a textarea element, then return element's own autocapitalization hint.

3. If element is an editing host or an editable element, then return the own autocapitalization hint of the editing host of element.

4. Assert: this step is never reached, since text input only occurs in elements that meet one of the above criteria.

6.7.7 Input modalities: the inputmode attribute

User agents can support the inputmode attribute on form controls (such as the value of textarea elements), or in elements in an editing host (e.g., using contenteditable).

The inputmode content attribute is an enumerated attribute that specifies what kind of input mechanism would be most helpful for users entering content.

The inputMode IDL attribute must reflect the inputmode content attribute, limited to only known values.

When inputmode is unspecified (or is in a state not supported by the user agent), the user agent should determine the default virtual keyboard to be shown. Contextual information such as the input type or pattern attributes should be used to determine which type of virtual keyboard should be presented to the user.

6.7.8 Input modalities: the enterkeyhint attribute

User agents can support the enterkeyhint attribute on form controls (such as the value of textarea elements), or in elements in an editing host (e.g., using contenteditable).

The enterkeyhint content attribute is an enumerated attribute that specifies what action label (or icon) to present for the enter key on virtual keyboards. This allows authors to customize the presentation of the enter key in order to make it more helpful for users.

The enterKeyHint IDL attribute must reflect the enterkeyhint content attribute, limited to only known values.

When enterkeyhint is unspecified (or is in a state not supported by the user agent), the user agent should determine the default action label (or icon) to present. Contextual information such as the inputmode, type, or pattern attributes should be used to determine which action label (or icon) to present on the virtual keyboard.