<link rel="stylesheet" href="http://www.jacklmoore.com/colorbox/example5/colorbox.css" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="http://www.jacklmoore.com/colorbox/jquery.colorbox.js"></script>
<script>
$(document).ready(function(){
$(".iframe").colorbox({iframe:true, width:"80%", height:"80%"});
$(".iframe").click();
});
</script>