use this script
1)
<script language="javascript" type="text/javascript">
function CallPrint(strid) {
var prtContent = document.getElementById(strid);
var WinPrint = window.open('', '', 'letf=0,top=0,width=1,height=1,toolbar=0,scrollbars=0,status=0');
WinPrint.document.write(prtContent.innerHTML);
WinPrint.document.close();
WinPrint.focus();
WinPrint.print();
WinPrint.close();
prtContent.innerHTML = strOldOne;
}
</script>
2)
<div id ="bill">
<%-- the content will be printed --%>.
3)call the Function
<asp:button id="BtnPrint" runat="server" text="Print" onclientclick="javascript:CallPrint('bill');" xmlns:asp="#unknown" />
</div>