Change RadTextBox value via Javascript

[Raymond]

I have the following coding

    <telerik:RadTextBox ID="RadTextBox1" runat="server" EnableEmbeddedSkins="false" BackColor="Red" ForeColor="White" />
 <asp:Button ID="btnTest" runat="server" OnClientClick="populateNTLogin('test');return false;" />
             <telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
       <script  type="text/javascript">
       

         function populateNTLogin(arg)
         {
         var textbox = window["<%= RadTextBox1.ClientID %>"];
             textbox.SetValue(arg);
             return false;
         }
        </script>
    </telerik:RadCodeBlock>

On clicking the button, the value is not populated to the textbox. Any idea how to solve this

[Baatezu]

function populateNTLogin(arg)
{
    var textbox = $find('<%= RadTextBox1.ClientID %>');
    textbox.set_value(arg);
}

I'd try that. I'm not sure that the window[] function is, so that's why I took it out. :)

The proper way to call the set_value is all lower case and with an underscore, as you can see at http://www.telerik.com/help/aspnet-ajax/input_clientsideradtextbox.html.
I took out return false because it seemed irrelevant in the code example you provided.