[javascript] How can Print Preview be called from Javascript?

It can be done using javascript. Say your html/aspx code goes this way:

<span>Main heading</span>
<asp:Label ID="lbl1" runat="server" Text="Contents"></asp:Label>
<asp:Label Text="Contractor Name" ID="lblCont" runat="server"></asp:Label>
<div id="forPrintPreview">
  <asp:Label Text="Company Name" runat="server"></asp:Label>
  <asp:GridView runat="server">

      //GridView Content goes here

  </asp:GridView
</div>

<input type="button" onclick="PrintPreview();" value="Print Preview" />

Here on click of "Print Preview" button we will open a window with data for print. Observe that 'forPrintPreview' is the id of a div. The function for Print preview goes this way:

function PrintPreview() {
 var Contractor= $('span[id*="lblCont"]').html();
 printWindow = window.open("", "", "location=1,status=1,scrollbars=1,width=650,height=600");
 printWindow.document.write('<html><head>');
 printWindow.document.write('<style type="text/css">@media print{.no-print, .no-print *{display: none !important;}</style>');
 printWindow.document.write('</head><body>');
 printWindow.document.write('<div style="width:100%;text-align:right">');

  //Print and cancel button
 printWindow.document.write('<input type="button" id="btnPrint" value="Print" class="no-print" style="width:100px" onclick="window.print()" />');
 printWindow.document.write('<input type="button" id="btnCancel" value="Cancel" class="no-print"  style="width:100px" onclick="window.close()" />');

 printWindow.document.write('</div>');

 //You can include any data this way.
 printWindow.document.write('<table><tr><td>Contractor name:'+ Contractor +'</td></tr>you can include any info here</table');

 printWindow.document.write(document.getElementById('forPrintPreview').innerHTML);
 //here 'forPrintPreview' is the id of the 'div' in current page(aspx).
 printWindow.document.write('</body></html>');
 printWindow.document.close();
 printWindow.focus();
}

Observe that buttons 'print' and 'cancel' has the css class 'no-print', So these buttons will not appear in the print.