This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

If a -webkit-mask-image is specified, -webkit-mask-attachment determines whether the mask image's position is fixed within the viewport, or scrolls along with its containing block.

/* Keyword values */
-webkit-mask-attachment: scroll;
-webkit-mask-attachment: fixed;
-webkit-mask-attachment: local;

/* Multiple values */
-webkit-mask-attachment: scroll, local;
-webkit-mask-attachment: fixed, local, scroll;

/* Global values */
-webkit-mask-attachment: inherit;
-webkit-mask-attachment: initial;
-webkit-mask-attachment: unset;



If scroll is specified, the mask image scrolls within the viewport along with the block that contains the mask image.
If fixed is specified, the mask image does not scroll with its containing element, instead remaining stationary within the viewport.

Formal definition

Initial valuescroll
Applies toall elements
Computed valueas specified
Animation typediscrete

Formal syntax


<attachment> = scroll | fixed | local


Fixing a mask image to the viewport

body {
  -webkit-mask-image: url('images/mask.png');
  -webkit-mask-attachment: fixed;


Not part of any standard.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Chrome No support 1 — 24Edge No support NoFirefox No support NoIE No support NoOpera No support NoSafari Full support 4WebView Android No support ≤37 — ≤37Chrome Android No support 18 — 25Firefox Android No support NoOpera Android No support NoSafari iOS Full support 3.2Samsung Internet Android No support 1.0 — 1.5


Full support  
Full support
No support  
No support
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.

See also