Passing values from javascript to code behind in ASP.NET

Question

I have a variable in aspx.cs when I click the Datagrid particular row;
Then from the javascript, I should get that value and pass into aspx.cs variable.

how to do this?

Samsara

what exactly you want to do, provide some code, what exactly you want to do with that variable at server side? – Pileus

There are many ways to do this however if you tell the purpose someone might advise you an alternate easier method. – Questor

Answer 1

Using html controls

First you use a hidden input control as:

<input type="hidden" value="" id="SendA" name="SendA" />

Second you add to that control the value you like to send on code behind using javascript as:

document.getElementById("SendA").value = "1";

And then on post back you get that value as:

Request.Form["SendA"]

Using asp.net Controls

The same way if you use asp.net control can be as:

<asp:HiddenField runat="server" ID="SendA" Value="" />
<script>
   document.getElementById("<%=SendA.ClientID%>").value = "1";
</script>

and get it on code behind with SendA.Value;

And of course you can use ajax calls to send on code behind values, or simple call url with url parameters that return no content.

Hayne

finally, so simple. Adding "<%=...%>" did the trick. thanks a lot Aristos. – Football

one thing I'd like to add is that if you're not seeing an updated value from the hiddenField, try creating a button to trigger a new event and you will see the value update(as opposed to relying on the pageLoad function event) – Pitchford