Web/CSS/mask-position

The mask-position CSS property sets the initial position, relative to the mask position layer set by mask-origin, for each defined mask image.

/* Keyword values */
mask-position: top;
mask-position: bottom;
mask-position: left;
mask-position: right;
mask-position: center;

/* <position> values */
mask-position: 25% 75%;
mask-position: 0px 0px;
mask-position: 10% 8em;

/* Multiple values */
mask-position: top right;
mask-position: 1rem 1rem, center;

/* Global values */
mask-position: inherit;
mask-position: initial;
mask-position: unset;

Syntax

One or more <position> values, separated by commas.

Values

<position>: One to four values representing a 2D position regarding the edges of the element's box. Relative or absolute offsets can be given. Note that the position can be set outside of the element's box.

Formal definition

Initial value	`center`
Applies to	all elements; In SVG, it applies to container elements excluding the `defs` element and all graphics elements
Inherited	no
Percentages	refer to size of mask painting area minus size of mask layer image (see the text for `background-position`)
Computed value	Consists of two keywords representing the origin and two offsets from that origin, each given as an absolute length (if given a <length>), otherwise as a percentage.
Animation type	repeatable list of simple list of length, percentage, or calc

Formal syntax

<position>#where <position> = [ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]where <length-percentage> = <length> | <percentage>

Examples

Setting mask position

CSS

#wrapper {
  border: 1px solid black;
  width: 250px;
  height: 250px;
}

#masked {
  width: 250px;
  height: 250px;
  background: blue linear-gradient(red, blue);
  mask-image: url(https://mdn.mozillademos.org/files/12676/star.svg);
  mask-repeat: no-repeat;
  mask-position: top right; /* Can be changed in the live sample */
  margin-bottom: 10px;
}

HTML

<div id="wrapper">
  <div id="masked">
  </div>
</div>
<select id="maskPosition">
  <option value="top">top</option>
  <option value="center">center</option>
  <option value="bottom">bottom</option>
  <option value="top right" selected>top right</option>
  <option value="center center">center center</option>
  <option value="bottom left">bottom left</option>
  <option value="10px 20px">10px 20px</option>
  <option value="60% 20%">60% 20%</option>
</select>

JavaScript

var maskPosition = document.getElementById("maskPosition");
maskPosition.addEventListener("change", function (evt) {
  document.getElementById("masked").style.maskPosition = evt.target.value;
});

Result

Specifications

Specification	Status	Comment
CSS Masking Module Level 1The definition of 'mask-position' in that specification.	Candidate Recommendation	Initial definition

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`mask-position`	Chrome Full support 1 Prefixed' Full support 1 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Edge Full support 18	Firefox Full support 53 Full support 53 No support 20 — 53 Disabled' Disabled' From version 20 until version 53 (exclusive): this feature is behind the `layout.css.masking.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 15 Prefixed' Full support 15 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Safari Full support 3.2 Prefixed' Full support 3.2 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	WebView Android Full support 2 Prefixed' Full support 2 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Chrome Android Full support 18 Prefixed' Full support 18 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Firefox Android Full support 53 Full support 53 No support 20 — 53 Disabled' Disabled' From version 20 until version 53 (exclusive): this feature is behind the `layout.css.masking.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android Full support 14 Prefixed' Full support 14 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Safari iOS Full support 3.2 Prefixed' Full support 3.2 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Samsung Internet Android Full support 1.0 Prefixed' Full support 1.0 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-
Support for three-value syntax of position	Chrome No support 1 — 68 Prefixed' No support 1 — 68 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Edge No support 18 — 79	Firefox No support 53 — 70 No support 53 — 70 No support 20 — 53 Disabled' Disabled' From version 20 until version 53 (exclusive): this feature is behind the `layout.css.masking.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera No support 15 — 55 Prefixed' No support 15 — 55 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Safari Full support 3.2 Prefixed' Full support 3.2 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	WebView Android No support 2 — 68 Prefixed' No support 2 — 68 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Chrome Android No support 18 — 68 Prefixed' No support 18 — 68 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Firefox Android Full support 53 Full support 53 No support 20 — 53 Disabled' Disabled' From version 20 until version 53 (exclusive): this feature is behind the `layout.css.masking.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Opera Android No support 14 — 48 Prefixed' No support 14 — 48 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Safari iOS Full support 3.2 Prefixed' Full support 3.2 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-	Samsung Internet Android No support 1.0 — 10.0 Prefixed' No support 1.0 — 10.0 Prefixed' Prefixed' Implemented with the vendor prefix: -webkit-

Legend

Full support: Full support
No support: No support
User must explicitly enable this feature.': User must explicitly enable this feature.
Requires a vendor prefix or different name for use.': Requires a vendor prefix or different name for use.

mask-position by Mozilla Contributors is licensed under CC-BY-SA 2.5.