ASP.NET AJAX Roundup

I ran across the following ASP.NET AJAX links over the last couple of weeks that I found interesting and useful, so I thought I would pass them along.

• Why ASP.NET AJAX UpdatePanels are dangerous - an article that warns of the overhead associated with using ASP.NET AJAX UpdatePanels to add "instant" AJAX capability to your website. Describes the use of JSON and PageMethods as a better performing alternative.
• How to improve ASP.NET AJAX error handling - shows how to create more robust and meaningful error messages than the standard popups within ASP.NET AJAX.
• AJAX Automated Testing and Debugging Tools - great list of options to consider for assisting with testing and debugging of AJAX applications. Please let me know via the comments of any experiences you have had with tools on this list.
• Force update of an ASP.NET AJAX UpdatePanel using JavaScript - How to manually force an UpdatePanel to update from JavaScript.