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.

Obsolete since Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4)
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.


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Note: This method is obsolete; you should use the FileReader method readAsDataURL() instead.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

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