How to maintain JavaScript values during PostBack in ASP.Net?

I have written one JavaScript to Calculate the TotalWeight based on two TextBox integer values. I multiplied thes开发者_如何学运维e two values and displayed in the 3rd TextBox Using JavaScript. But the problem is, I have one radiobuttonlist, in its selectedindexchanged event, the value I got in the 3rd TextBox gets disappeared. How to solve this?

My JavaScript is

  <script type="text/javascript">
   function TotalWeight()
        {
            var D1 = document.getElementById('<%=txtD1.ClientID%>');
            var SectionWgt = document.getElementById('<%=txtSectionWeight.ClientID%>');
            var TotalWgt = 0*1;
            TotalWgt = parseFloat(D1.value) * parseFloat(SectionWgt.value);

            if(isNaN(TotalWgt))
                document.getElementById('<%=txtTotalWgt.ClientID%>').innerText = "0.000";
            else
                document.getElementById('<%=txtTotalWgt.ClientID%>').innerText = TotalWgt.toFixed(3);
       }
  </script>

  <asp:TextBox ID="txtD1" runat="server" Width="136px" onkeyup="return TotalWeight();"></asp:TextBox>

After you calculate and assign the value to your Total Textbox, then put that value in a hidden field as well, and then on postback reassign that value to the textbox from the hidden Field.

Read the value of the textbox in when the radio button event fires and posts back - and then write it back to the textbox afterwards.

I would imagine that when the event fires and the page posts back, the third text box reverts to its original value - capture the new value and write it back to the box during the event.

use hidden field to store values. just use

[intput type="hidden" id="someid">]

after that you can use the value using $("#someid").val() Try, this helped me.