is #

::: section-content The is global attribute allows you to specify that a standard HTML element should behave like a defined custom built-in element (see Using custom elements for more details).

This attribute can only be used if the specified custom element name has been successfully defined in the current document, and extends the element type it is being applied to. :::

Examples #

::: section-content The following code is taken from our word-count-web-component{target="_blank"} example ( see it live also{target="_blank"}).

::: code-example [js]{.language-name}

// Create a class for the element
class WordCount extends HTMLParagraphElement {
  constructor() {
    // Always call super first in constructor
    super();

    // Constructor contents omitted for brevity
    // …
  }
}

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

:::

::: code-example [html]{.language-name}

<p is="word-count"></p>

::: :::

Specifications #

::: _table #

Specification #

HTML Standard
[# attr-is]{.small}

:::

Browser compatibility #

::: _table Desktop Mobile

     Chrome    Edge   Firefox   Internet Explorer   Opera   Safari   WebView Android   Chrome Android   Firefox for Android   Opera Android   Safari on IOS   Samsung Internet

is 67 79 63 No 54 No 67 67 63 48 No 9.0 :::