---
title: is
slug: Web/HTML/Global_attributes/is
translation_of: Web/HTML/Global_attributes/is
original_slug: Web/HTML/Globale_Attribute/is
---
<div>{{HTMLSidebar("Global_attributes")}}</div>

<p><span class="seoSummary">The <strong><code>is</code></strong> <a href="/en-US/docs/Web/HTML/Global_attributes">global attribute</a> allows you to specify that a standard HTML element should behave like a defined custom built-in element (see <a href="/en-US/docs/Web/Web_Components/Using_custom_elements">Using custom elements</a> for more details).</span></p>

<p>This attribute can only be used if the specified custom element name has been successfully <a href="/en-US/docs/Web/API/CustomElementRegistry/define">defined</a> in the current document, and extends the element type it is being applied to.</p>

<h2 id="Examples">Examples</h2>

<p>The following code is taken from our <a href="https://github.com/mdn/web-components-examples/tree/master/word-count-web-component">word-count-web-component</a> example (<a href="https://mdn.github.io/web-components-examples/word-count-web-component/">see it live also</a>).</p>

<pre class="brush: js">// Create a class for the element
class WordCount extends HTMLParagraphElement {
  constructor() {
    // Always call super first in constructor
    super();

    // Constructor contents ommitted for brevity
    ...

  }
}

// Define the new element
customElements.define('word-count', WordCount, { extends: 'p' });</pre>

<pre class="brush: html">&lt;p is="word-count"&gt;&lt;/p&gt;</pre>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('HTML WHATWG', "custom-elements.html#attr-is", "is")}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>



<p>{{Compat("html.global_attributes.is")}}</p>

<h2 id="See_also">See also</h2>

<ul>
 <li>All <a href="/en-US/docs/Web/HTML/Global_attributes">global attributes</a>.</li>
</ul>