>>See the remarks section at http://msdn.microsoft.com/en-us/library/ms228122%28v=vs.100%29.aspx
>
>Thanks, this is a valuable link.
>
>>The following resources may also help, although they primarily relate to IE10:
>>http://stackoverflow.com/questions/6983732/ie10-user-agent-causes-asp-net-to-not-send-back-set-cookie-ie10-not-setting-coo
>>http://connect.microsoft.com/VisualStudio/feedback/details/662275/asp-net-user-agent-sniffing-and-ie10-internet-explorer-10
>>http://support.microsoft.com/kb/2600088
>>http://support.microsoft.com/kb/2600217
>>http://www.hanselman.com/blog/BugAndFixASPNETFailsToDetectIE10CausingDoPostBackIsUndefinedJavaScriptErrorOrMaintainFF5ScrollbarPosition.aspx
>
>Yes, I see some have come up with various workarounds to adjust non supported option as time goes by, either on a temporary basis or permanent.
>
>This one, however, is very basic. A focus on a field should continue to be supported in all browsers. I would certainly expect Microsoft to adjust IE 11 for that. Have you heard anything that this support was removed? ...or that it would be fixed in an update?

Its possible that it could be fixed in an update, but Windows Server 2003 would be 10 years old now, and may only be receiving security updates (http://support.microsoft.com/lifecycle/default.aspx?LN=en-us&x=11&y=8&p1=3198). This update may correct the issue (see issue 2): http://support.microsoft.com/kb/2836939. If you can't control or update the server, the browser file would be an alternative.

With Web Forms, the server uses the browser files to determine what capabilities the user's browser has and adjusts the output based on that. With IE 11, it likely can't determine that javascript is supported and doesn't render the appropriate client side code to focus on the correct element.

Also, if focus is your only issue and you are using HTML5, you could try setting the autofocus attribute: http://www.w3schools.com/tags/att_input_autofocus.asp