PopUp Print Automatically

function popupprint() {
            var prtContent = document.getElementById('<%=content.ClientID %>');
            var WinPrint = window.open('', '', 'letf=0,top=0,toolbar=0,scrollbars=0,status=0');
            WinPrint.document.write(prtContent.innerHTML);
            WinPrint.document.close();
            WinPrint.focus();
            WinPrint.print();
            WinPrint.close();
        }