AJAX FilteredTextBoxExtender allow carriage return <p>I have a multi-line text box that I am using an AJAX FilteredTextBoxExtender to limit the user input to only numbers. I'd like to also allow the user to add a new line by using the enter key. I've searched and haven't found anything that works. Does anyone know how to do this?</p> <p>Thanks in advance!</p> <p>Here's my code for reference:</p> <pre><code>&lt;asp:TextBox ID="txtEIDEntryBox" runat="server" CssClass="PrettyEntryBox" TextMode="MultiLine" Height="300px" Width="100px"&gt;&lt;/asp:TextBox&gt; &lt;ajaxToolkit:FilteredTextBoxExtender ID="ftbeEID" runat="server" TargetControlID="txtEIDEntryBox" FilterType="Custom" ValidChars="0123456789"&gt;&lt;/ajaxToolkit:FilteredTextBoxExtender&gt; </code></pre>