Web/API/HTMLCanvasElement/mozGetAsFile

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 non-standard, Firefox-specific the HTMLCanvasElement method mozGetAsFile() returns a memory-based File object representing the image contained in the canvas.

Syntax

canvas.mozGetAsFile(name, type);

Parameters

name: A DOMString indicating the file name to give the file representing the image file in memory.
type Optional: A DOMString which specifies the image file format to use when creating the new image file. The default type is image/png. For other options, see our Image file type and format guide.

Return value

A File object representing the image contained in the canvas. The file's data is entirely located in memory until such time as it is explicitly written to disk.

Examples

This example creates an image file from the <canvas> element on the page, then uses a FileReader to read the image data from the file.

HTML

<canvas id="canvas" width="100" height="100"></canvas>
<p><a href="#" id="link">Click here to try out mozGetAsFile()</a>.</p>

JavaScript

The following code uses mozGetAsFile() to create a File object from the canvas and appends it as an image to the page by loading it as a data URL using the readAsDataURL() method. Then a new <img> element is created using the new data URL.

function draw() {
  var canvas = document.getElementById('canvas');
  var ctx = canvas.getContext('2d');
 
  ctx.fillStyle = 'rgb(200, 0, 0)';
  ctx.fillRect(10, 10, 55, 50);
 
  ctx.fillStyle = 'rgba(0, 0, 200, 0.5)';
  ctx.fillRect(30, 30, 55, 50);

  var link = document.getElementById('link');
  link.addEventListener('click', copy);
}
    
function copy() {
  var canvas = document.getElementById('canvas');
  var f = canvas.mozGetAsFile('test.png');
  var reader = new FileReader();
  reader.readAsDataURL(f);
      
  reader.onloadend = function() {
   var newImg = document.createElement('img');
   newImg.src = reader.result;
   document.body.appendChild(newImg);
  }
}

window.addEventListener('load', draw);

Specifications

Not part of any specification.

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
`mozGetAsFile` Deprecated'Non-standard'	Chrome No support No	Edge No support No	Firefox No support 4 — 74 Notes' No support 4 — 74 Notes' Notes' `mozGetAsFile()` was deprecated in Firefox 26 (in 2013) and was removed entirely in Firefox 74.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 4	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

Full support: Full support
No support: No support
Non-standard. Expect poor cross-browser support.': Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.': Deprecated. Not for use in new websites.
See implementation notes.': See implementation notes.

HTMLCanvasElement.mozGetAsFile() by Mozilla Contributors is licensed under CC-BY-SA 2.5.