How can I print form through Java Script ?

Java Script for printing aspx form.

function CallPrint() {
var prtContent = document.getElementById('ExcelExport');
var WinPrint = window.open('', '', 'top=0,width=800,height=700,left=120,scrollbars=yes,status=0');
WinPrint.document.write(prtContent.innerHTML);
WinPrint.document.close();
WinPrint.focus();
WinPrint.print();
WinPrint.close();
prtContent.innerHTML = strOldOne;

}

call this function on print button on client click.