CSS Basic User Interface Module Level 3 (CSS User Interface 3) Implementation Report

Introduction

This report was prepared to document the current implementation status of the CSS Basic User Interface Module Level 3 (CSS User Interface 3) specification as of 6 July 2023 and is based on current test results available in the W3C Conformance Test Harness.

Implementations

Ten user agents, built from seven rendering implementations, were tested across six operating systems.

• Complete list of user agents tested

Tests

The 6 July 2023 revision of the CSS User Interface 3 test suite was used. The test suite consists of 106 tests, 15 of which test for optional behavior.

These tests are available in several host language variants:

• HTML 5
• XHTML 1.1
• XHMLT 1.1 for Printers

Some tests only apply to certain language variants; the results for each tested implementation are reported for each tested language variant. Also, not all tests are applicable to each implementation; for example, a browser which implements HTML but not XHTML is not tested for XHTML.

Results

In summary, the results show that all 91 tests for required behavior were passed by at least two of the tested implementations. In addition, 4 of 15 tests for optional behavior were passed by at least two of the tested implementations.

Results were gathered from implementation reports submitted by user agent vendors as well as the general public via the W3C Conformance Test Harness.

• Summary table of test result counts per rendering implementation
• Detailed results for each rendering implementation
• BFO
• Blink
• Edge
• Gecko
• PaleMoon
• Presto
• WebKit