drag and drop not working in firefox [duplicate]

Question

I have implemented drag and drop functionality in JQuery and html5 , its working great in chrome but stuck in Firefox following is my code where i am alerting id of dropped image which appears as undefined in Firefox following is my code , please help . jsfiddle: http://jsfiddle.net/rajutikale/2R6p8/

View:

<!-- dragable image --> 
<a href="#?w=976" rel="popup1" id="<?=$album['album_id'].'-'.$data->content_id?>" class="poplight album_photos"><img  id="<?=$album['album_id'].'-'.$data->content_id?>" draggable="true" ondragstart="drag(event)" ondragover="allowDrop(event)" alt="" src="<?=$imagePath?>"></a>

<input type="hidden" id="<?='wall'.$data->content_id?>" value="<?=$data->wall_id?>" />
<input type="hidden" id="<?='type'.$data->content_id?>" value="<?=$data->content_type?>" />
<input type="hidden" id="<?='user'.$data->content_id?>" value="<?=$_SESSION['user_type']?>" />

<!-- dropable area -->
<div class="" style="z-index: 1; position:fixed; right:124px; top:60px" id="div1" ondrop="drop(event);;" ondragover="allowDrop(event);"> <a href="#"><img id="dropzon_image"src="<?php echo IMAGE_PATH_HTTP?>babbler_btn.jpg" alt="" border="0" style="cursor: pointer; cursor: hand; "/></a>
    <div id="overlay" style="display:none;z-index: 2;  position:fixed; right:0px; top:32px; cursor: pointer;border-color: blueviolet;">
        <img id="drop_image" src="<?php echo IMAGE_PATH_HTTP?>drop_image.jpg" alt="" border="1" style="cursor: pointer; cursor: hand; " />
    </div>
</div>

JS:

function allowDrop(ev) {
    ev.preventDefault();
}

function drag(ev) {
    ev.dataTransfer.setData("Text", ev.target.id);
    $("#div1").find("#overlay").slideDown();
    setTimeout(function () {
        $("#overlay").hide();
    }, 4000);
}

function drop(ev) {
    var id = ev.dataTransfer.getData("Text"); /*implimented solution*/
    alert(id);
    ev.preventDefault();
    var action = 'download';
    var wall_id = '62';
    var stat = 'Album';
    var cnt = '0';
    var user_type = 'R';
    var status = do_download(action, wall_id, stat, cnt, user_type);
    $("#overlay").hide();
    // ev.target.appendChild(document.getElementById(data));
}

Answer 1

According to https://developer.mozilla.org/en-US/docs/Web/Events/dragstart set data to null (like in html part of the example, or in the event function) with:

event.dataTransfer.setData('text/plain', null);

Chromium doesn't need of that.