May need modified depending on downloaded file type - depending on the browser, PDF's will try to open in the actual iFrame


// FROM - http://stackoverflow.com/questions/156686/how-to-start-automatic-download-of-a-file-in-internet-explorer


$(function() {
   $(window).bind('load', function() {
      $('.download').delay(1500).append('<iframe width="0" height="0" frameborder="0" src="[YOUR FILE SRC]"></iframe>'); 
   });
});




<div class="download"></div>

Download AutoStart

JavaScript