set linkbutton as default button for asp:panel in asp.net

Possible Duplicate:
Link Button on the page and set it as default button, work fine in IE but not in Mozila

How to set linkbutton as default button for asp:panel in asp.net? I know a button can be set as default but my application uses linkbuttons for all forms. Any suggestion how it can be done.

EDIT:

Now i tried this, It works in firefox as well but my javascript validation (ie) onclient click of my linkbutton doesn't work why?

var __defaultFired = false;

        function WebForm_FireDefaultButton(event, target) {
            var element = event.target || event.srcElement;

            if (!__defaultFired && event.keyCode == 13 && !(element && (element.tagName.toLowerCase() == "textarea"))) {
                var defaultButton;

                if (__nonMSDOMBrowser)
                    defaultButton = document.getElementById(target);
                else
                    defaultButton = document.all[target];

                if (defaultButton) {
                    if (typeof (defaultButton.click) != "undefined")
                        defaultButton.click();
                    else
                        eval(unescape(defaultButton.href.replace("javascript:", "")));

                    event.cancelBubble = true;

                    if (event.stopPropagation) event.stopPropagation();
                    return false;
                }
            }
            return true;
        }

Second EDIT:

I was able make my custom linkbutton control work but couldn't able to hook OnClientClick to it. Source using-panel-defaultbutton-property-with-linkbutton-control-in-asp-net.

and i did this,

<%@ Register Namespace="App_Code" TagPrefix="ac" %>
<asp:Label runat="server" ID="lblHello" />
<asp:Panel runat="server" DefaultButton="lbHello">
    First name: <asp:TextBox runat="server" ID="txtFirstName" />
    <ac:LinkButtonDefault ID="lbHello" runat="server" Text="Click me" 
        OnClientClick="javascript:alert('hai');" OnClick="lbHello_Click" />
</asp:Panel>

My Clientside function doesn't work why? Any suggestion.

Rather than use a custom control you could take the simple approach of adding an attribute to handle the textbox's onKeyPress event. This correctly handles pressing Enter from the textbox and triggering the LinkButton's event. The downside to this approach is that any LinkButton OnClientClick event will not be triggered in Firefox, which is related to the issue described in that blog post you linked to. It will only be triggered when the user actually clicks on the link with their mouse. However, in IE, it will trigger from both the textbox and from being clicked on directly.

Solution #1 - The code to add the attribute is as follows:

protected void Page_Load(object sender, EventArgs e)
{
    txtFirstName.Attributes.Add("onKeyPress",
        "javascript:if (event.keyCode == 13) __doPostBack('" + lbHello.ClientID + "','')");
}

Try that and see if it fits your needs. Just bear in mind the limitation I described earlier.

Now, if you want the above limitation to go away, one of the comments from that blog post showed an approach that appears to work correctly. I've modified it to get rid of the StringBuilder and converted it to C#.

Solution #2 - The code to add the function and register it is as follows:

protected void Page_PreRender(object sender, EventArgs e)
{
    string addClickFunctionScript = @"function addClickFunction(id) {
           var b = document.getElementById(id);
           if (b && typeof(b.click) == 'undefined')
             b.click = function() {
               var result = true;
               if (b.onclick) result = b.onclick();
               if (typeof(result) == 'undefined' || result)
                 eval(b.getAttribute('href'));
             }
         };";

    string clickScript = String.Format("addClickFunction('{0}');", lbHello.ClientID);

    Page.ClientScript.RegisterStartupScript(this.GetType(), "addClickFunctionScript", addClickFunctionScript, true);
    Page.ClientScript.RegisterStartupScript(this.GetType(), "click_" + lbHello.ClientID, clickScript, true);
}

Page Markup - The page mark-up is the same for both of the aforementioned solutions:

<asp:Label runat="server" ID="lblHello" />
<asp:Panel ID="Panel1" runat="server" DefaultButton="lbHello">
    First name:
    <asp:TextBox runat="server" ID="txtFirstName" />
    <asp:LinkButton ID="lbHello" runat="server" Text="Click me" OnClick="lbHello_Click"                 
         OnClientClick="javascript:alert('Hello, World!');"/>
</asp:Panel>

In both cases a custom control is not needed to achieve this type of functionality. Keep it simple.