Update pattern attribute (#35874)

* Update `pattern` attribute Mention implicit anchoring, and update the RegExp flag. Makes this description consistent with the dedicated [`pattern` attribute documentation](/en-US/docs/Web/HTML/Attributes/pattern). * Update files/en-us/web/html/element/input/index.md Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> * Update files/en-us/web/html/element/input/index.md Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> --------- Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
mdn · Sep 17, 2024 · bf1775f · bf1775f
1 parent 415caa6
commit bf1775f
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/files/en-us/web/html/element/input/index.md b/files/en-us/web/html/element/input/index.md
@@ -534,9 +534,12 @@ A few additional non-standard attributes are listed following the descriptions o
 
 - [`pattern`](/en-US/docs/Web/HTML/Attributes/pattern)
 
-  - : Valid for `text`, `search`, `url`, `tel`, `email`, and `password`, the `pattern` attribute defines a regular expression that the input's [`value`](#value) must match in order for the value to pass [constraint validation](/en-US/docs/Web/HTML/Constraint_validation). It must be a valid JavaScript regular expression, as used by the {{jsxref("RegExp")}} type, and as documented in our [guide on regular expressions](/en-US/docs/Web/JavaScript/Guide/Regular_expressions); the `'u'` flag is specified when compiling the regular expression, so that the pattern is treated as a sequence of Unicode code points, instead of as {{Glossary("ASCII")}}. No forward slashes should be specified around the pattern text.
+  - : Valid for `text`, `search`, `url`, `tel`, `email`, and `password`, the `pattern` attribute is used to compile a regular expression that the input's [`value`](#value) must match in order for the value to pass [constraint validation](/en-US/docs/Web/HTML/Constraint_validation). It must be a valid JavaScript regular expression, as used by the {{jsxref("RegExp")}} type, and as documented in our [guide on regular expressions](/en-US/docs/Web/JavaScript/Guide/Regular_expressions). No forward slashes should be specified around the pattern text. When compiling the regular expression:
 
-    If the `pattern` attribute is present but is not specified or is invalid, no regular expression is applied and this attribute is ignored completely. If the pattern attribute is valid and a non-empty value does not match the pattern, constraint validation will prevent form submission.
+    1. the pattern will be implicitly wrapped with `^(?:` and `)$`, such that the match is required against the _entire_ input value, i.e., `^(?:<pattern>)$`.
+    2. the `'v'` flag is specified so that the pattern is treated as a sequence of Unicode code points, instead of as {{Glossary("ASCII")}}.
+
+    If the `pattern` attribute is present but is not specified or is invalid, no regular expression is applied and this attribute is ignored completely. If the pattern attribute is valid and a non-empty value does not match the pattern, constraint validation will prevent form submission. If the [`multiple`](/en-US/docs/Web/HTML/Attributes/multiple) is present, the compiled regular expression is matched against each comma separated value.
 
     > [!NOTE]
     > If using the `pattern` attribute, inform the user about the expected format by including explanatory text nearby. You can also include a [`title`](#title) attribute to explain what the requirements are to match the pattern; most browsers will display this title as a tooltip. The visible explanation is required for accessibility. The tooltip is an enhancement.