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The element() CSS function defines an <image> value generated from an arbitrary HTML element. This image is live, meaning that if the HTML element is changed, the CSS properties using the resulting value are automatically updated.

A particularly useful scenario for using this would be to render an image in an HTML <canvas> element, then use that as a background.

On Gecko browsers, you can use the non-standard document.mozSetImageElement() method to change the element being used as the background for a given CSS background element.


element( id )


The ID of an element to use as the background, specified using the HTML attribute #id on the element.


These examples can be viewed live in builds of Firefox that support -moz-element().

A somewhat realistic example

This example uses a hidden <div> as a background. The background element uses a gradient, but also includes text that is rendered as part of the background.

<div style="width:400px; height:400px; background:-moz-element(#myBackground1) no-repeat;">
  <p>This box uses the element with the #myBackground1 ID as its background!</p>

<div style="overflow:hidden; height:0;">
  <div id="myBackground1" style="width:1024px; height:1024px; background-image: linear-gradient(to right, red, orange, yellow, white);">
  <p style="transform-origin:0 0; transform: rotate(45deg); color:white;">This text is part of the background. Cool, huh?</p>

The <div> element with the ID "myBackground1" is used as the background for the content including the paragraph "This box uses the element with the #myBackground1 ID as its background!".


A somewhat more bizarre example

This example uses a hidden <button> element in a repeating pattern as its background. This demonstrates that you can use arbitrary elements as background, but doesn't necessarily demonstrate good design practices.

<div style="width:400px; height:100px; background:-moz-element(#myBackground2);">

<div style="overflow:hidden; height:0;">
  <button id="myBackground2" type="button">Evil button!</button>



Specification Status Comment
CSS Image Values and Replaced Content Level 4 Working Draft Actually now deferred to CSS4.

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Firefox (Gecko) Chrome Internet Explorer Opera Safari
Basic support 4.0 (2.0) [*] -moz 未实现 未实现 未实现 未实现
Feature Firefox Mobile (Gecko) Android IE Phone Opera Mobile Safari Mobile
Basic support 4.0 (2.0) [*] -moz 未实现 未实现 未实现 未实现

[*] Usage limited to the background and background-image CSS properties.

See also