title: jQuery validate bug with required validation on IE10 in compatibility mode to IE7/IE8
body: <p>there is a <a href="http://social.msdn.microsoft.com/Forums/ie/en-US/449ca2d0-038f-4c1d-b926-9b499106242c/internet-explorer-10-changing-required-attribute-in-compatibility-mode" rel="nofollow">Confirmed bug in IE10 compatibility mode</a> that won't be fixed for IE10:</p>
  
  <p><strong>In IE10 in compatibility to IE8</strong><br>
  $element.get(0).getAttribute("required") returns "" when the required attribute is missing, this causes ALL fields to be required   </p>
  
  <p><strong>In IE10 in compatibility to IE7</strong><br>
  $element.get(0).getAttribute("required") returns null in all cases.<br>
  so you can't use required as an attribute on the element  </p>
  
  <p>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</p>