Gridview Hidden Field - how can I get a hidden field value using JavaScript?
<p>I have Gridview like this:</p>

<pre><code> &lt;asp:GridView ID="gvPartsSearchResult" runat ="server" CssClass="MRJ_TextGrid"&gt; 
    &lt;Columns&gt;
        &lt;asp:TemplateField HeaderText="Select"&gt;
            &lt;ItemTemplate&gt;
                &lt;asp:RadioButton 
                    ID="rdButton" 
                    runat="server" 
                    AutoPostBack ="true"            
                    onclick="javascript:CheckOtherIsCheckedByGVIDMore()"/&gt;
                &lt;asp:HiddenField 
                    ID="hdnFileExtension" 
                    runat="server" 
                    Value ='&lt;%#Bind("FILE_EXTENSION")%&gt;'/&gt;
            &lt;/ItemTemplate&gt;
        &lt;/asp:TemplateField&gt;
    &lt;/Columns&gt;
&lt;/asp:GridView&gt;
</code></pre>

<p>I want to read the hidden field value when the user clicks on the radio button.  Can anyone help me with this?</p>
