there is a [Confirmed bug in IE10 compatibility mode](http://social.msdn.microsoft.com/Forums/ie/en-US/449ca2d0-038f-4c1d-b926-9b499106242c/internet-explorer-10-changing-required-attribute-in-compatibility-mode) that won't be fixed for IE10:

**In IE10 in compatibility to IE8**  

$element.get(0).getAttribute("required") returns "" when the required attribute is missing, this causes ALL fields to be required 

**In IE10 in compatibility to IE7**  

$element.get(0).getAttribute("required") returns null in all cases.  

so you can't use required as an attribute on the element 

The plugin Author doesn't plan to handle compatibility views as users shouldn't encounter it, but developers that just want to check something in old IE might want to