A better alternative to using alert() for debugging.
We've all used, and unfortunately some people continue to use, alert() to help debug JavaScript. Thankfully the Microsoft Ajax Library has a Sys.Debug class that exposes methods for logging messages to the browser’s JavaScript console. For reference:
To log a message to the console use: Sys.Debug.trace(“Log this message to the console”);
To dump an object use: Sys.Debug.traceDump(someObject);
If you don’t have a JavaScript console download the Web Development Helper for IE, and Firebug for Firefox, or add the following textarea element to your page:
<textarea id=”TraceConsole” rows=”50” cols=”50”></textarea>
This will display all your trace messages in the textarea.