mask-position

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The mask-position CSS property sets the initial position, relative to the mask position layer defined 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;
/*  values */
mask-position: 25% 75%;
/*  values */
mask-position: 0px 0px;
mask-position: 1cm 2cm;
mask-position: 10ch 8em;
/* Multiple values */
mask-position: 0px 0px, center;
/* Global values */
mask-position: inherit;
mask-position: initial;
mask-position: unset;

Initial value	`0% 0%`
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`)
Media	visual
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
Canonical order	the unique non-ambiguous order defined by the formal grammar

Syntax

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

Values

<position>: Is a <position>, that is 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 syntax

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

Example

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;
});

Specifications

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

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	1.0-webkit	53.0 (53.0)	?	?	4.0-webkit

Feature	Android	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	?	53.0 (53.0)	?	?	?

Syntax

Values

Formal syntax

Example

CSS

HTML

JavaScript

Specifications

Browser compatibility

Document Tags and Contributors