Saving changes of table is not permitted.

Tools -> Options->Designers->Table and Database Designers -> Uncheck

Jquery Check dropdown change

  $(function ()
  { 
    $('#ddlReaderMagnification').change(function () {     
      if ($(this).val() > 0)
        {
        $('#spnMagnification').css({ "display": "none" });
      }
      else {
        $('#spnMagnification').css({ "display": "inline" });
      }
    });
  });

Get checked radiobutton value on the basis of name

var rbLensGroup = $('input[name="rbLensGroup"]:checked');
if (rbLensGroup != null && rbLensGroup.val() == "rbReaders")
{
  --Do code here
}

Remove attribute on the basis of name

$("input[name$='ctl00$ContentPlaceHolderBody$btnBack']").removeAttr("disabled");

Disabled control inside table

  $("#tblMain").find('input[type=submit], select, input[type=text], input[type=button], textarea, a').removeAttr('onclick').not('#lbtnReleaseLock').removeAttr('onclick').removeAttr('href').attr({ 'disabled': 'disabled', 'id': '' });

how to show empty data text in repeater

======1st Way==========
<FooterTemplate>
        <tr id="trEmpty" runat="server" visible="false">
            <td colspan = "3" align = "center">
                No records found.
            </td>
        </tr>
 </FooterTemplate>

======Code Behind======
    if (dt.Rows.Count == 0)
    {
        Control FooterTemplate = rptCustomers.Controls[rptCustomers.Controls.Count - 1].Controls[0];
        FooterTemplate.FindControl("trEmpty").Visible = true;
    }

======2nd Way========
<FooterTemplate>
    <asp:Label ID="defaultItem" runat="server"
        Visible='<%# YourRepeater.Items.Count == 0 %>' Text="No items found" />
</FooterTemplate>

======3rd Way========
<FooterTemplate>
    <asp:Label ID="lblEmptyData" runat="server" Visible='<%# ((Repeater)Container.NamingContainer).Items.Count == 0 %>' Text="No items found" />
</FooterTemplate>

How to disable all controls on page in asp.net

We have several ways to do this:

Jquery
     a) Specific control type
        $('input[type=submit], select, input[type=text], input[type=button], input[type=checkbox], input[type=radio], textarea, a').not('#ContentPlaceHolderMiddle_btnTEsting').removeAttr('onclick').removeAttr('href').attr({ 'disabled': 'disabled' });
       
     b) All Controls
        $("*").not('#ContentPlaceHolderMiddle_btnTEsting').removeAttr('onclick').removeAttr("href").attr({ "disabled": "disabled" });

Javascript

       var vControl = document.forms[0].elements;
       var vControlAnchor = document.forms[0].getElementsByTagName('a');
     
       for (j = 0; j < vControlAnchor.length; j++) {
         vControlAnchor[j].removeAttribute('href');
         //document.forms[0].getElementsByTagName('a')[0].removeAttribute('href');
       }
       for(i = 0; i< vControl.length; i++)
       {
         vControl[i].disabled = true;
       }