Print div content using javascript - Asp.net

Script

 <script type="text/javascript">

        function printPartOfPage(elementId) {

            var printContent = document.getElementById(elementId);

            var windowUrl = 'about:blank';

            var uniqueName = new Date();

            var windowName = 'Print' + uniqueName.getTime();

            var printWindow = window.open(windowUrl, windowName, 'left=50000,top=50000,width=0,height=0');

            printWindow.document.write(printContent.innerHTML);

            printWindow.document.close();

            printWindow.focus();

            printWindow.print();

            printWindow.close();

        }

</script>

Button click

<asp:Button ID="btnPrint" runat="server" Text="Print" OnClientClick="JavaScript: printPartOfPage('printablediv');"/>

*Set div id as printablediv