HTMLCanvasElement: mozOpaque property

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Non-standard: This feature is not standardized. We do not recommend using non-standard features in production, as they have limited browser support, and may change or be removed. However, they can be a suitable alternative in specific cases where no standard option exists.

The non-standard HTMLCanvasElement.mozOpaque property is a boolean value reflecting the moz-opaque HTML attribute of the <canvas> element. It lets the canvas know whether or not translucency will be a factor. If the canvas knows there's no translucency, painting performance can be optimized.

Note: This has been standardized as setting the alpha option to false when creating a drawing context with HTMLCanvasElement.getContext(). Use of mozOpaque should be avoided. Firefox will stop supporting it in the future.

Value

A boolean value.

Examples

Given this <canvas> element:

html

<canvas id="canvas" width="300" height="300" moz-opaque></canvas>

You can get or set the mozOpaque property. For example, you could conditionally set it to true if mimeType === 'image/jpeg', or similar, to gain performance in your application when translucency is not needed.

const canvas = document.getElementById("canvas");
console.log(canvas.mozOpaque); // true
// deactivate it
canvas.mozOpaque = false;

Specifications

Not part of any standard.

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`mozOpaque` Deprecated Non-standard	Chrome – No support Chrome footnote No support	Edge – No support Edge footnote No support	Firefox – Full support Firefox 3.5 (Release date: 2009-06-30) footnote Full support	Opera – No support Opera footnote No support	Safari – No support Safari footnote No support	Chrome Android – No support Chrome Android footnote No support	Firefox for Android – Full support Firefox for Android 4 (Release date: 2011-03-29) footnote Full support	Opera Android – No support Opera Android footnote No support	Safari on iOS – No support Safari on iOS footnote No support	Samsung Internet – No support Samsung Internet footnote No support	WebView Android – No support WebView Android footnote No support	WebView on iOS – No support WebView on iOS footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: Non-standard. Check cross-browser support before using.
: Deprecated. Not for use in new websites.

HTMLCanvasElement: mozOpaque property

Value

Examples

Specifications

Browser compatibility

Legend

See also