This is a simple demo of how to make calls to a web server from within JavaScript without reloading the page (and without messing with hidden frames!). This is the technique put to so much good use by the Google geeks working on Gmail. The implications of being able to do this in web apps are big!

Update 06/03/05: Just found an article for developers on Apple which says the last two points above aren't possible. You can't request anything from a domain different to that of the parent page. It's not clear whether this is the default security setting or whether it is never possible.

The example below does none of these wonderous things. It is supposed to be the bare minimum amount of code for an XML HTTP request to work. All it does is request this page and put the result into the text area. Just click the link at the bottom of the page.

This code is a rip-off of slightly more in-depth examples here, by a guy who I've come across before when looking into fun with FOAF.

My colleague Paul Fitzsimons @ iQ Content recently pointed out this article which summarises the technique Google is using on it's new services. It calls it Ajax - Asynchronous JavaScript and XML.