Loading an image to a from

In browsers supporting the File API, you can use the FileReader constructor to read files once they have been selected by the user.

Example

document.getElementById('picField').onchange = function (evt) {
    var tgt = evt.target || window.event.srcElement,
        files = tgt.files;
    
    // FileReader support
    if (FileReader && files && files.length) {
        var fr = new FileReader();
        fr.onload = function () {
            document.getElementById(outImage).src = fr.result;
        }
        fr.readAsDataURL(files[0]);
    }
    
    // Not supported
    else {
        // fallback -- perhaps submit the input to an iframe and temporarily store
        // them on the server until the user's session ends.
    }
}

Browser support

  • IE 10
  • Safari 6.0.2
  • Chrome 7
  • Firefox 3.6
  • Opera 12.02

Where the File API is unsupported, you cannot (in most security conscious browsers) get the full path of a file from a file input box, nor can you access the data. The only viable solution would be to submit the form to a hidden iframe and have the file pre-uploaded to the server. Then, when that request completes you could set the src of the image to the location of the uploaded file.

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