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Introduce customelementregistry global attribute #12000

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Introduce customelementregistry global attribute #12000

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c0253ac
Introduce customelementregistry global attribute
Dec 8, 2025
6cb566e
Add keep element custom element registry null
Dec 9, 2025
beb2ec6
Address PR review feedback for customelementregistry attribute
Apr 24, 2026
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40 changes: 38 additions & 2 deletions source
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Original file line number Diff line number Diff line change
Expand Up @@ -3415,6 +3415,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
<li><dfn data-x-href="https://dom.spec.whatwg.org/#valid-attribute-local-name">valid attribute local name</dfn></li>
<li><dfn data-x-href="https://dom.spec.whatwg.org/#valid-element-local-name">valid element local name</dfn></li>
<li><dfn data-x-href="https://dom.spec.whatwg.org/#is-a-global-custom-element-registry">is a global custom element registry</dfn></li>
<li><dfn data-x-href="https://dom.spec.whatwg.org/#concept-element-keep-custom-element-registry-null">keep element custom element registry null</dfn></li>
</ul>

<p>The following features are defined in <cite>UI Events</cite>: <ref>UIEVENTS</ref></p>
Expand Down Expand Up @@ -12622,6 +12623,7 @@ interface <dfn interface>HTMLElement</dfn> : <span>Element</span> {
[<span>CEReactions</span>, <span data-x="xattr-ReflectSetter">ReflectSetter</span>] attribute DOMString <span data-x="dom-writingSuggestions">writingSuggestions</span>;
[<span>CEReactions</span>, <span data-x="xattr-ReflectSetter">ReflectSetter</span>] attribute DOMString <span data-x="dom-autocapitalize">autocapitalize</span>;
[<span>CEReactions</span>] attribute boolean <span data-x="dom-autocorrect">autocorrect</span>;
[<span>CEReactions</span>, <span data-x="xattr-Reflect">Reflect</span>] attribute boolean <dfn attribute for="HTMLElement" data-x="dom-element-customElementRegistry">customElementRegistry</dfn>;

[<span>CEReactions</span>] attribute [<span>LegacyNullToEmptyString</span>] DOMString <span data-x="dom-innerText">innerText</span>;
[<span>CEReactions</span>] attribute [<span>LegacyNullToEmptyString</span>] DOMString <span data-x="dom-outerText">outerText</span>;
Expand Down Expand Up @@ -13976,6 +13978,7 @@ https://software.hixie.ch/utilities/js/live-dom-viewer/?%3C%21DOCTYPE%20HTML%3E%
<li><code data-x="attr-autocorrect">autocorrect</code></li>
<li><code data-x="attr-fe-autofocus">autofocus</code></li>
<li><code data-x="attr-contenteditable">contenteditable</code></li>
<li><code data-x="attr-customelementregistry">customelementregistry</code></li>
<li><code data-x="attr-dir">dir</code></li>
<li><code data-x="attr-draggable">draggable</code></li>
<li><code data-x="attr-enterkeyhint">enterkeyhint</code></li>
Expand Down Expand Up @@ -77597,6 +77600,14 @@ console.assert(el instanceof SpiderMan); // upgraded!</code></pre>
<code>CustomElementRegistry</code> object, it intentionally cannot be changed any further. This
simplifies reasoning about code and allows implementations to optimize.</p>

<h4>The <code data-x="attr-customelementregistry">customelementregistry</code> attribute</h4>

<p> The
<dfn element-attr for="html-global"><code data-x="attr-customelementregistry">customelementregistry</code></dfn>
attribute is used to specify whether the parser should be
<span data-x="look up a custom element registry">looking up a custom element registry</span>
when the parser runs <span>Create an element for the token</span>. The value is boolean.</p>


<h4><dfn data-x="custom-element-upgrades">Upgrades</dfn></h4>

Expand Down Expand Up @@ -139837,8 +139848,15 @@ dictionary <dfn dictionary>StorageEventInit</dfn> : <span>EventInit</span> {
<li><p>Let <var>is</var> be the value of the "<code data-x="attr-is">is</code>" attribute in
<var>token</var>, if such an attribute exists; otherwise null.</p></li>

<li><p>Let <var>registry</var> be the result of <span data-x="look up a custom element
registry">looking up a custom element registry</span> given <var>intendedParent</var>.</p></li>
<li><p>Let <var>registry</var> be null if
<code data-x="attr-customelementregistry">customelementregistry</code> attribute exists;
otherwise let <var>registry</var> be the result of
<span data-x="look up a custom element registry">looking up a custom element registry</span>
given <var>intendedParent</var>.</p></li>
Comment thread
ja-y-son marked this conversation as resolved.

<li><p>Let <var>keepRegistryNull</var> be true if
<code data-x="attr-customelementregistry">customelementregistry</code> attribute exists;
otherwise false.

<li><p>Let <var>definition</var> be the result of <span data-x="look up a custom element
definition">looking up a custom element definition</span> given <var>registry</var>,
Expand Down Expand Up @@ -139927,6 +139945,10 @@ dictionary <dfn dictionary>StorageEventInit</dfn> : <span>EventInit</span> {
with the <code>form</code> element pointed to by the <span><code data-x="">form</code> element
pointer</span> and set <var>element</var>'s <span>parser inserted flag</span>.</p></li>

<li><p>If <var>keepRegistryNull</var> is true, set <var>element</var>'s
<span>keep element custom element registry null</span>
to true.

<li><p>Return <var>element</var>.</p></li>
</ol>
</div>
Expand Down Expand Up @@ -144648,6 +144670,15 @@ document.body.appendChild(text);
data-x="escaping a string">escaped as described below</span> in <i>attribute mode</i>,
followed by a U+0022 QUOTATION MARK character (&quot;).</p>

<p>If the element does not have a
<code data-x="attr-customelementregistry">customelementregistry</code> attribute in its
attribute list, and <var>current node</var>'s
<span data-x="element-custom-element-registry">custom element registry</span> is not the
same as the result of
<span data-x="look up a custom element registry">looking up a custom element
registry</span> given <var>current node</var>'s parent element, then append
"<code data-x=""> customelementregistry=&quot;&quot;</code>".</p>

<p>For each attribute that the element has, append a U+0020 SPACE character, the <span
data-x="attribute's serialized name">attribute's serialized name as described below</span>, a
U+003D EQUALS SIGN character (=), a U+0022 QUOTATION MARK character (&quot;), the
Expand Down Expand Up @@ -153378,6 +153409,11 @@ interface <dfn interface>External</dfn> {
<td> "<code data-x="attr-crossorigin-anonymous-keyword">anonymous</code>";
"<code data-x="attr-crossorigin-use-credentials-keyword">use-credentials</code>";
the empty string
<tr>
<th> <code data-x="">customelementregistry</code>
<td> <span data-x="attr-class">HTML elements</span>
<td> Whether the element should use scoped custom element registry
<td> <span>Boolean attribute</span>
<tr>
<th> <code data-x="">data</code>
<td> <code data-x="attr-object-data">object</code>
Expand Down
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