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 HTMLCanvasElement.mozGetAsFille() method returns a File object representing the image contained in the canvas; this file is a memory-based file, with the specified name. If type is not specified, the image type is image/png.


<var>canvas.mozFetchAsStream(name, type);</var>


A DOMString indicating the file name.
type Optional
A DOMString indicating the image format. The default type is image/png.

Return value

A File object representing the image contained in the canvas.


Example: Using mozGetAsFile()

HTML snippet:

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

The following code uses mozGetAsFile to create a File object from the canvas and appends it as an image to the page using FileReader.readAsDataURL():

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.onloadend = function () {
    var newImg = document.createElement("img");
    newImg.src = reader.result;

window.addEventListener("load", draw);


Not part of any specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support Not supported 4.0 (2) Not supported Not supported Not supported
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support Not supported Not supported 4.0 (2) Not supported Not supported Not supported

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API Canvas HTMLCanvasElement Method Reference Référence