PDF hide Jquery Modal in IE

I am displaying a PDF in an <iframe> using a jQuery modal popup on button click. This is works fine in all browsers except IE10, where the displayed PDF hides the modal dialog.

Dropping IE10 support is not an option.

I tried using z-index. In this jsfiddle, the modal is outside of the body but nothing works. I could hide the pdf on popup or change the position of it, but my client don't want that. Also I tried var text = prompt("Alert", "textbox's intial text"); - old javascript, but client don't like that look. My TL don't want to use iframe in modal. Isn't anyway I can take pdf behind HTML?

HTML:

<body>
    <div id='ClickMe'>Click here!</div>
    <br/>
    <div>This is more than likely an Adobe issue where it thinks it should be in front all the time no matter what, however it is very annoying that you can't open a dialog over a PDF.  Click on the 'Click here!' text above to see this issue occur.  Interesting enough if you click the Discuss button in JSFiddle it does the same thing.</div>
    
</body>

jQuery:

var $Dialog_div;

function fnOpenDialog() {
    var str = '<div id="dialog" style="display: none;height:60%;" title="On Hold Reason" align="center">'+'<br />'+'<textarea id="messageTextBox" cols="32" rows="3" style="resize:none"></textarea>'+'<div class="row" align="center">'+'<br />'+'</div>'+'<br />'+'</div>';

     $Dialog_div = $(str).prependTo('body');
//    $Dialog_div = $('<div id=\'ThisDialog\'>Hello</div>').prependTo('body');

    $Dialog_div = $('#dialog').dialog({
        autoOpen: true,
        draggable: true,
        resizable: true,
        title: 'Dialog',
        modal: true,
        stack: true,
        height: ($(window).height() * 0.95),
        width: ($(window).width() * 0.9),

       buttons: {
         'Yes': function() {
             alert($('#messageTextBox').val());
              $Dialog_div.dialog('close');
          },
           'No': function(){
           alert('No');
              $Dialog_div.dialog('close');
       }

      }

    });

}

$('#ClickMe').click(fnOpenDialog);

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