title: Validate AJAX Toolkit Combobox Regular Expression Validator
body: <p>I was wondering if it was possible to validate the <code>ajax toolkit combobox</code> with a regular expression validator.  I allow the user to enter values, but only want certain values ( <code>regex [0-9]{0,1}[0-9]{1}|-7|-8|-9</code>) to be allowed.  I could use the custom validator, but I would need to also create javascript function to validate on the client side.  If there is a better way I would love to hear it.  Thanks.  Here is the combobox code:</p>
  
  <pre><code>    &lt;asp:ComboBox CssClass="required" DropDownStyle="Simple"  
       ID="DaysDeployed" Width="50" runat="server"&gt;
          &lt;asp:ListItem Selected="True" Text="" Value="" /&gt;
          &lt;asp:ListItem Text="Refused" Value="-7" /&gt;
          &lt;asp:ListItem Text="Don't Know" Value="-8" /&gt;
          &lt;asp:ListItem Text="Missing Data" Value="-9" /&gt;
      &lt;/asp:ComboBox&gt;
  </code></pre>