打印特定元素內容

function ClickToPrint(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=450,height=300');
         printWindow.document.write(printContent.innerHTML);
         printWindow.document.close();
         printWindow.focus();
         printWindow.print();
         printWindow.close();
        }