Joshua Eichorn’s Blog: AJAX Answers:

The questions answered include:

• How can I find out whether a connection is broken?
• Why would you want to use HTML_AJAX when there are far better tools for the job, pure javascript solutions such as prototype or jquery?
• What is the best way to ‘degrade’ a website when Javascript/XMLHttpRequest support is disabled?
• When utilizing an AJAX API such as Google Maps, how do you execute embedded Javascript commands in a page generated on-the-fly?

Pretty good stuff

(Via PHPDeveloper.org.)