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.

Deprecated since Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4)
This feature has been removed from the Web standards. Though some browsers may still support it, it is in the process of being dropped. Do not use it in old or new projects. Pages or Web apps using it may break at any time.


The getAsDataURL provides a data: URL that encodes the entire contents of the referenced file.

Note: This method is obsolete; you should use the FileReader method readAsDataURL() instead.


var url = instanceOfFile.getAsDataURL();


A string representing a data: URL


// fileInput is a HTMLInputElement: <input type="file" id="myfileinput" multiple>
var fileInput = document.getElementById("myfileinput");

// files is a FileList object (similar to NodeList)
var files = fileInput.files;

// array with acceptable file types
var accept = ["image/png"];

// img is a HTMLImgElement: <img id="myimg">
var img = document.getElementById("myimg");

// if we accept the first selected file type
if (accept.indexOf(files[0].mediaType) > -1) {
  // display the image
  // same as <img src="data:image/png,<imagedata>">
  img.src = files[0].getAsDataURL();


Not part of any specification.

See also


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

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