Untitled

event.dataTransfer.files undefined in firefox
document.getElementById("folder_files").addEventListener("drop", function(event) {
   event.preventDefault();
   event.stopPropagation();
   alert(event.dataTransfer.files[0].fileName);
}, false);

'0' ...
        'size' => "30379"
        'lastModifiedDate' ...
        'fileSize' => "30379"
        'name' => "bg.png"
        'type' => "image/png"
        'webkitRelativePath' => ""
        'fileName' => "bg.png"
        'webkitSlice' => "function webkitSlice() { [native code] }"
    'length' => "1"
    'item' => "function item() { [native code] }"

0' ...
        'size' => "30379"
        'type' => "image/png"
        'mozSlice' => "function mozSlice() {
    [native code]
}"
        'name' => "bg.png"
        'mozFullPath' => ""
    'length' => "1"
    'item' => "function item() {
    [native code]
}"