Another piece of helpful information to do with iframes and IE, taken from: http://www.dmitri.me

“IE has bug which deletes session data and brakes functionality of website. In other browsers all is working fine.
Here is example in PHP:

<?php
print_r($_SESSION);
//output:
//Array ()
?>

After half day of breaking brain and Google really fantastic solution for this problem, but no one of them didn’t solved our problem. So Mika found that if markup have empty src attribute, IE makes an empty request which breaks session data. So solution is simple check if there any empty src attributes and hrefs in link tag.

Was:

<img src="" alt="An image" id="img" />

You need to remove this empty attribute or if you don’t need this for javascript remove IMG tag at all.”