<input id="prtButton" type="button" value="Print" onclick="CallPrint('<%= GridView1.ClientID %>');" />
function CallPrint( strid )
var prtContent = document.getElementById( strid );
var WinPrint = window.open('', '', 'left=0,top=0,width=1050,height=600,toolbar=1,scrollbars=1,status=0');
WinPrint.document.write( prtContent.innerHTML );
hope this is what you wanted....