pass parameter to one function in the code behind in C# from javascript
<p>I am trying to pass parameter to one function in the code behind in C# from javascript</p>

<pre><code>&lt;script type="text/javascript"&gt;
    $(document).ready(function () {

        $("#some_id").click(function () {
            var id = document.getElementById('HiddenField2');
            var a = &lt;%=btn_Click(id)%&gt;;
        });

    });
&lt;/script&gt;
&lt;asp:HiddenField ID="HiddenField2" runat="server" Value='&lt;%# DataBinder.Eval(Container.DataItem, "item_id")%&gt;' /&gt;
code behind
 public string btn_Click(String item_id)
    {
        /*do some thing*/

        return null;
    }  
</code></pre>

<p>But this piece of code always giving me error of context. That id is not defined in this context.
Can some please let me know what wrong i am doing?</p>
