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Specification https://github.com/whatwg/html/pull/7908 Summary The <input pattern> attribute allows developers to specify a regular expression pattern against which the input’s values are checked for validity. <label> Part number: <input pattern="[0-9][A-Z]{3}" name="part" title="A part number is a digit followed by three uppercase letters."> </label> When the pattern attribute was first implemented, these regular expressions were compiled without any RegExp flags. In 2014, the HTML Standard changed this by implicitly enabling the u flag for the pattern attribute, enabling better Unicode support (including support for Unicode character properties like \p{Letter}). This change shipped in Chrome 53. <https://chromestatus.com/feature/4753420745441280> Now, we’re taking this to the next level by enabling the new RegExp v flag <https://v8.dev/features/regexp-v-flag> instead of u, enabling the use of set notation, string literal syntax, and Unicode properties of strings. (Context: The RegExp v flag is a JavaScript language feature which previously went through the Blink Intents process and shipped in Chrome 112 <https://chromestatus.com/feature/5144156542861312>. This new ChromeStatus entry is specifically about integrating it with the HTML pattern attribute.) Blink component Blink>Forms <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3EForms> Search tags unicode <https://chromestatus.com/features#tags:unicode>, regexp <https://chromestatus.com/features#tags:regexp>, pattern <https://chromestatus.com/features#tags:pattern>, validation <https://chromestatus.com/features#tags:validation> TAG review TAG review status Not applicable Risks Interoperability and Compatibility The spec patch at https://github.com/whatwg/html/pull/7908 lists the potentially breaking changes. Some patterns that previously would compile, now throw an early error with the v flag — specifically those with a character class including either an unescaped special character or a double punctuator. We expect such patterns to be rare. To validate this assumption we’ve added a UseCounter called HTMLPatternRegExpUnicodeSetIncompatibilitiesWithUnicodeMode <https://chromestatus.com/metrics/feature/popularity#HTMLPatternRegExpUnicodeSetIncompatibilitiesWithUnicodeMode> in M112, which tracks patterns in any JavaScript u RegExps generated via the HTML pattern attribute that would throw if they were used with the v flag. Importantly, note that any throwing pattern gracefully degrades — it simply behaves as if the pattern attribute wasn’t present, resulting in inputElement.validity.valid === true for any input value. Consequently, the only compatibility risk is that some value/pattern combinations that would previously result in inputElement.validity.valid being false now result in it being true. Thus, for every UseCounter hit, it could still be that there is no actual breakage — the UseCounter just gives us the upper bound. The currently available data from Beta suggests the UseCounter hits for 0.0393% of Chrome page loads. Gecko: Positive (Mozilla standards position request <https://github.com/mozilla/standards-positions/issues/745>, implementation tracking issue <https://bugzilla.mozilla.org/show_bug.cgi?id=pattern-v>) WebKit: Positive (WebKit standards position request <https://github.com/WebKit/standards-positions/issues/132>, implementation tracking issue <https://bugs.webkit.org/show_bug.cgi?id=pattern-v>) Web developers: No signals Other signals: Debuggability The pattern attribute is already well-supported in DevTools and other tooling; no changes are necessary. Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes Is this feature fully tested by web-platform-tests <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> ? Pull Request: https://github.com/web-platform-tests/wpt/pull/38547 Flag name N/A Requires code in //chrome? False Tracking bug https://bugs.chromium.org/p/chromium/issues/detail?id=1412729 Sample links https://mathiasbynens.be/demo/pattern-u-vs-v Estimated milestones M114 Link to entry on the Chrome Platform Status https://chromestatus.com/feature/5149507107422208 -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CADizRgaAq4FwzJbUqLQVo%2BQdd_V0PT7rBr510OGe8fenHA%3D3HQ%40mail.gmail.com.
