I used the jquery plugin Cluetip to create popups for a system whereby Hebrew text is displayed.  In Firefox it displayed correctly but in IE I just got ????

Cluetip uses a query string of the type a href="filename.php?c=$var1&u=$var2" where filename.php is the html for the popup window.

At first I thought the problem was with the filename.php and tried eveything under the sun but then found that urlencode is the answer, as follows:

href="filename.php?c=urlencode($var1)&u=urlencode($var2)"