element()
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
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.
Syntax
element(id)
where:
- id
-
The ID of an element to use as the background, specified using the HTML attribute #id on the element.
Formal syntax
<element()> =
element( <id-selector> )
<id-selector> =
<hash-token>
Examples
These examples work 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 id="target-box">
<p>This box uses the element with the #my-background ID as its background!</p>
</div>
<div id="background-container">
<div id="my-background">
<p>This text is part of the background. Cool, huh?</p>
</div>
</div>
#target-box {
width: 400px;
height: 400px;
background: -moz-element(#my-background) no-repeat;
}
#background-container {
overflow: hidden;
height: 0;
}
#my-background {
width: 1024px;
height: 1024px;
background-image: linear-gradient(to right, red, orange, yellow, white);
}
#my-background p {
transform-origin: 0 0;
rotate: 45deg;
color: white;
}
The <div> element with the ID "my-background" is used as the background for the content including the paragraph "This box uses the element with the #my-background ID as its background!".
Page Preview
This
example based on Vincent De Oliveira's creates a preview of
the <div id="css-source"> inside <div id="css-result">.
HTML
<div id="css-source">
<h1>Page Preview</h1>
</div>
<div id="css-result"></div>
CSS
#css-result {
background: -moz-element(#css-source) no-repeat;
width: 256px;
height: 32px;
background-size: 80%;
border: dashed;
}
Result
Specifications
| Specification |
|---|
| CSS Images Module Level 4 # element-notation |
Browser compatibility
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