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-moz-context-properties

Non-standard
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.

The -moz-context-properties property can be used within privileged contexts in Firefox to share the values of specified properties of the element with a child SVG image.

If you reference an SVG image in a webpage (such as with the <img> element or as a background image), the SVG image can coordinate with the embedding element (its context) to have the image adopt property values set on the embedding element. To do this the embedding element needs to list the properties that are to be made available to the image by listing them as values of the -moz-context-properties property, and the image needs to opt in to using those properties by using values such as the context-fill value.

Syntax

/* Keyword values */
-moz-context-properties: fill;
-moz-context-properties: fill, stroke;

/* Global values */
-moz-context-properties: inherit;
-moz-context-properties: initial;
-moz-context-properties: unset;

Values

fill
Expose the fill value set on the image to the embedded SVG.
stroke
Expose the stroke value set on the image to the embedded SVG.
fill-opacity
Expose the fill-opacity value set on the image to the embedded SVG.
stroke-opacity
Expose the stoke-opacity value set on the image to the embedded SVG.

Formal definition

Initial value none
Applies to Any element that can have an image applied to it, for example as a background-image, border-image, or list-style-image.
Inherited yes
Computed value as specified
Animation type discrete

Formal syntax

none | [ fill | fill-opacity | stroke | stroke-opacity ]#

Examples

Exposing fill and stroke to an SVG image

In this example we have a simple SVG embedded using an <img> element.

You first need to specify on the embedding element the properties whose values you wish to expose to the embedded SVG, using the -moz-context-properties property. For example:

.img1 {
  width: 100px;
  height: 100px;
  -moz-context-properties: fill, stroke;
  fill: lime;
  stroke: purple;
}

Now that you've done this, the SVG image can use the values of the fill and stroke properties, for example:

<img class="img1" src="data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg'>
                       <rect width='100%' height='100%' stroke-width='30px'
                       fill='context-fill red' stroke='context-stroke' fill-opacity='0.5'/></svg>">

Here we've set the image src to a data URI containing a simple SVG image; the <rect> inside has been made to take its fill and stroke values from the fill and stroke set on the <img> element by giving them the context-fill/context-stroke keywords in their values, along with a fallback color for the fill (red) which will be used in the case that the SVG is loaded standalone in a top-level window (where it will have no context element to provide context values). Note that if a color is set directly on the SVG, but then the context color is also specified, the context color overrides the direct color.

Note: You can find a working example on Github.

Specifications

Not part of any standard.

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
-moz-context-properties No No 55
Disabled
55
Disabled
With the preference set to false, the property still works with SVGs via chrome:// or resource:// URLs
Disabled From version 55: this feature is behind the svg.context-properties.content.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
No No No
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
-moz-context-properties No No 55
Disabled
55
Disabled
With the preference set to false, the property still works with SVGs via chrome:// or resource:// URLs
Disabled From version 55: this feature is behind the svg.context-properties.content.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
No No No

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-context-properties