This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The ::backdrop CSS pseudo-element is a box rendered immediately below any element rendered in fullscreen mode (and above any lower elements in the stack).
dialog::backdrop {
background: rgba(255,0,0,.25);
}
Fullscreen elements are part of the top layer's stack, i.e., they are rendered in front of all other content. The ::backdrop pseudo-element can be used to style or hide the underlying document.
::backdrop does not inherit from any element and is not inherited from. No restrictions are made on what properties apply to this pseudo-element.
Syntax
::backdrop
Specifications
| Specification | Status | Comment |
|---|---|---|
| Fullscreen API The definition of '::backdrop' in that specification. |
Living Standard | Initial definition. |
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 32.0 webkit 37.0 |
(Yes)ms | 47 (47) [1] | 11 ms | No support | No support |
on <dialog> |
32.0 webkit 37.0 |
No support | No support | No support | No support | No support |
| on fullscreen | No support | (Yes)ms | 47 (47) [1] | 11 ms | No support | No support |
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | No support | (Yes)ms | 47.0 (47) [1] | No support | No support | No support |
on <dialog> |
No support | No support | No support | No support | No support | No support |
| on fullscreen | No support | (Yes)ms | 47.0 (47) [1] | No support | No support | No support |
[1] See bug 1064843
See also
:fullscreenpseudo-class<dialog>HTML element

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