Tab Index in User Controls And .aspx pages

http://www.codeproject.com/Articles/17952/Using-a-TabIndex-with-a-UserControl-containing-NET

Ajax Toolkit Focusing
http://dotnetguts.blogspot.in/2009/04/textbox-set-focus-on-load-while-using.html

Master Pages

http://weblogs.asp.net/caseyroach/archive/2008/07/10/dismiss-the-modalpopupextender-with-esc-or-enter-key.aspx

To get of a server control in master page through JavaScript is
   var id=documnet.getElementById('<%= controlID.ClientID %>');


var id=documnet.getElementById('<%= txtUserId.ClientID %>');