>>Right, but the missing part form my side is how do you do this from the server-side code?
>>
>>I have no problem adding OnClick code, but how do you do it afterwards in server-side?
>>
>>Can you please show some example?
>
>Everytime a page is processed, it is either a postback or a link to a new page. In both approaches, what I do is to pass a LXMessage in the query string, which contains a message to show. When the incoming hits is processed, if such a field is found in the query string, it will make it appear as an alert message, but only processed at the end of the page so everything has been loaded and thus you can see the message on top of the HTML display.

I've tried to search if we have something like this already, I found some cases where we used QueryString, but none that match your idea.

However, in one of the pages I also found this

this.ScriptManager1.AsyncPostBackErrorMessage = "Please choose a match";

in the catch block.

Since our site uses AJAX, perhaps that's the way to return messages to the user?

I'll need to research on this technique too.

Here is something I found
http://fredrik.nsquared2.com/viewpost.aspx?PostID=394&showfeedback=true