title: Ajax FilteredTextBox Extender is not working
body: <p>I did everything correct and its not showing me any error. I just want to allow user to enter numbers but its allowing all the characters.<br>
  Here is my source</p>
  
  <pre><code>&lt;asp:ScriptManager ID="ScriptManager1" runat="server"&gt;
          &lt;/asp:ScriptManager&gt;
          &lt;asp:FilteredTextBoxExtender ID="FilteredTextBoxExtender1" runat="server" TargetControlID="TextBox1" FilterType="Numbers"&gt;
          &lt;/asp:FilteredTextBoxExtender&gt;
          &lt;asp:Label ID="Label1" runat="server" Text="Phone No"&gt;&lt;/asp:Label&gt;
  &amp;nbsp;&lt;asp:TextBox ID="TextBox1" runat="server"&gt;&lt;/asp:TextBox&gt;
  </code></pre>