TextBox filtering according to RadioButton selection
<p>I've a <code>RadioButtonList</code> and a <code>TextBox</code>. Accordindg to RadioButtonList selection, I want to filtrering textbox.</p>

<pre><code> &lt;asp:RadioButtonList ID="RadioButtonList1"  runat="server"  AutoPostBack="True" OnSelectedIndexChanged="RadioButtonList1_SelectedIndexChanged"&gt;
      &lt;asp:ListItem Text="NUMBER" Value="1" Selected="True"&gt;&lt;/asp:ListItem&gt;
      &lt;asp:ListItem Text="TEXT" Value="2"&gt;&lt;/asp:ListItem&gt;
&lt;/asp:RadioButtonList&gt;

 &lt;asp:TextBox ID="txtID" runat="server"&gt;
</code></pre>

<p>When I click listitem with value <code>1</code>, user can enter number to textbox. value <code>2</code>, number + text.
also I want to set the length. Can someone show me how to do this?</p>
