Thanks Svetlina !
I tried the below:
var tabStrip = $find( "<%= RadTabStrip1.ClientID %>");
var tab = tabStrip.findTabByText( "Reports");
However, I was getting SharePoint message 'Code Block are not allowed in this file
So, I modified the web.config file
For some reason SharePoint does not like <%= %> block.
But now I am getting 'An unexpected error has occurred'
Is there anything else I am missing?