how to make asp:button a default button on entering text to asp:textbox

How can I set default button after text is entered into a text box. This is what I have so far. But it doesn't work

<td>
                    <asp:Label ID="displayrowLabel" runat="server" Text="# of Rows Displayed:"></asp:Label>
                    <asp:TextBox ID="displayRowQuery" runat="server"></asp:TextBox>
                    <asp:Button ID="displayRowButton" r开发者_运维问答unat="server" Text="Click" OnClick="ddlPageItems_SelectedIndexChanged" />
                    <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="displayRowQuery"  ValidationExpression="[1-9][0-9]*"  ErrorMessage="Wrong Input" />
                </td>               
            </tr>
        </table>            
    </PagerTemplate>

I tried adding some jquery to handle this:

<script type="text/javascript">
    $("displayRowQuery").keyup(function (event) {
        if (event.keyCode == 13) {
            $("displayRowButton").click();
        }
    });

You can also set a default button for an asp:panel if you have a group of controls you need a default button for.

Basically:

<asp:Panel ID="aPanel" runat="server" DefaultButton="btnSubmit2">

    <!-- Some Controls Here -->

    <asp:Button UseSubmitBehavior="true" ID="btnSubmit2" Text="Submit" runat="server" onclick="btnSubmit2_Click" />

</asp:Panel>

http://www.aspnettutorials.com/tutorials/controls/defaultbutton-panel-aspnet.aspx

You're missing the "#" in your id selector:

    $("#displayRowQuery").keyup(function (event) {
        if (event.keyCode == 13) {
            $("#displayRowButton").click();
        }
    });

Edit: As @Nicolás has pointed out, you may have to substitute the id selectors with ClientId like this:

$("#displayRowQuery") => $("#<% = displayRowQuery.ClientId %>") 
$("#displayRowButton") >= $("#<% = displayRowButton.ClientId %>")