The HTMLCanvasElement interface provides properties and methods for manipulating the layout and presentation of <canvas> elements. The HTMLCanvasElement interface also inherits the properties and methods of the HTMLElement interface.
HTMLCanvasElement
Properties
Inherits properties from its parent, HTMLElement.
-
HTMLCanvasElement.height -
The
heightHTML attribute of the<canvas>element is a positiveintegerreflecting the number of logical pixels (or RGBA values) going down one column of the canvas. When the attribute is not specified, or if it is set to an invalid value, like a negative, the default value of150is used. If no [separate] CSS height is assigned to the<canvas>, then this value will also be used as the height of the canvas in the length-unit CSS Pixel. -
HTMLCanvasElement.width -
The
widthHTML attribute of the<canvas>element is a positiveintegerreflecting the number of logical pixels (or RGBA values) going across one row of the canvas. When the attribute is not specified, or if it is set to an invalid value, like a negative, the default value of300is used. If no [separate] CSS width is assigned to the<canvas>, then this value will also be used as the width of the canvas in the length-unit CSS Pixel. -
HTMLCanvasElement.mozOpaqueNon-Standard Deprecated -
Is a boolean value reflecting the
moz-opaqueHTML 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. This is only supported in Mozilla-based browsers; use the standardizedcanvas.getContext('2d', { alpha: false })instead. -
HTMLCanvasElement.mozPrintCallbackNon-Standard -
Is a
functionthat is Initially null. Web content can set this to a JavaScript function that will be called when the canvas is to be redrawn while the page is being printed. When called, the callback is passed a "printState" object that implements the MozCanvasPrintState interface. The callback can get the context to draw to from the printState object and must then call done() on it when finished. The purpose ofmozPrintCallbackis to obtain a higher resolution rendering of the canvas at the resolution of the printer being used. See this blog post.
Methods
Inherits methods from its parent, HTMLElement.
-
HTMLCanvasElement.captureStream()Experimental -
Returns a
CanvasCaptureMediaStreamTrackthat is a real-time video capture of the surface of the canvas. -
HTMLCanvasElement.getContext() -
Returns a drawing context on the canvas, or null if the context ID is not supported. A drawing context lets you draw on the canvas. Calling getContext with
"2d"returns aCanvasRenderingContext2Dobject, whereas calling it with"webgl"(or"experimental-webgl") returns aWebGLRenderingContextobject. This context is only available on browsers that implement WebGL. -
HTMLCanvasElement.toDataURL() -
Returns a data-URL containing a representation of the image in the format specified by the
typeparameter (defaults topng). The returned image is in a resolution of 96dpi. -
HTMLCanvasElement.toBlob() -
Creates a
Blobobject representing the image contained in the canvas; this file may be cached on the disk or stored in memory at the discretion of the user agent. -
HTMLCanvasElement.transferControlToOffscreen()Experimental -
Transfers control to an
OffscreenCanvasobject, either on the main thread or on a worker.
Obsolete methods
-
HTMLCanvasElement.mozGetAsFile()Non-Standard Deprecated -
Returns a
Fileobject representing the image contained in the canvas; this file is a memory-based file, with the specifiedname. Iftypeis not specified, the image type isimage/png.
Events
Listen to these events using addEventListener().
-
webglcontextcreationerror -
Fired if the user agent is unable to create a
WebGLRenderingContextorWebGL2RenderingContextcontext. -
webglcontextlost -
Fired if the user agent detects that the drawing buffer associated with a
WebGLRenderingContextorWebGL2RenderingContextobject has been lost. -
webglcontextrestored -
Fired if the user agent restores the drawing buffer for a
WebGLRenderingContextorWebGL2RenderingContextobject.
Specifications
| Specification |
|---|
| HTML Standard # htmlcanvaselement |
Browser compatibility
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
HTMLCanvasElement |
1
|
12
|
1.5
|
9
|
9
|
2
|
1
|
18
|
4
|
10.1
|
1
|
1.0
|
captureStream |
51
|
79
|
43
|
No
|
36
|
11
|
51
|
51
|
43
|
36
|
11
|
5.0
|
getContext |
1
|
12
|
1.5
|
9
|
9
|
2
|
1
|
18
|
4
|
10.1
|
1
|
1.0
|
height |
1
|
12
|
1.5
|
9
|
9
|
3
|
1
|
18
|
4
|
10.1
|
1
|
1.0
|
mozFetchAsStream |
No
|
No
|
13-23
|
No
|
No
|
No
|
No
|
No
|
14-23
|
No
|
No
|
No
|
mozGetAsFile |
No
|
No
|
4-74
mozGetAsFile() was deprecated in Firefox 26 (in 2013) and was removed entirely in Firefox 74.
|
No
|
No
|
No
|
No
|
No
|
4
|
No
|
No
|
No
|
mozOpaque |
No
|
No
|
3.5
|
No
|
No
|
No
|
No
|
No
|
4
|
No
|
No
|
No
|
toBlob |
50
|
79
12-79
|
18
|
10
|
37
|
11
|
50
|
50
|
18
|
37
|
11
|
5.0
|
toDataURL |
1
|
12
|
2
|
9
|
9
|
4
|
≤37
|
18
|
4
|
10.1
|
3
|
1.0
|
transferControlToOffscreen |
69
|
79
|
44
|
No
|
56
|
No
|
69
|
69
|
No
|
48
|
No
|
10.0
|
webglcontextcreationerror_event |
9
|
12
|
49
|
11
|
12
|
5.1
|
≤37
|
25
|
49
|
12
|
8
|
1.5
|
webglcontextlost_event |
9
|
12
|
4
|
11
|
12
|
5.1
|
≤37
|
25
|
4
|
12
|
8
|
1.5
|
webglcontextrestored_event |
9
|
12
|
4
|
11
|
12
|
5.1
|
≤37
|
25
|
4
|
12
|
8
|
1.5
|
width |
1
|
12
|
1.5
|
9
|
9
|
3
|
1
|
18
|
4
|
10.1
|
1
|
1.0
|
See also
- HTML element implementing this interface:
<canvas>
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https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement
