The basic framework of an Ajax-enabled web page. The following JavaScript shows how to send a request for an XML file and how to receive that request. Of course, in a real life scenario, you'll have to implement better error trapping and actually do something with the XML that gets returned.

This is a brief revision to my previous snippet. It is still what it was: a small, simple system for using XMLHttpRequest without using globals.

I'll put the API spec in the code this time, so as not to clutter the front page further.

Changes:

Changed name to HTTPRequest (far more accurate)
Added HEAD requests
Shortened code by making a GenericRequest function
Used a better method for getting an XMLHttpRequest object (checks multiple MS versions and implements the latest one)

A simple AJAX class. The code for the class is provided as well as example HTML and PHP code for usage.

This is a simple script to provide basic cross-platform XML request functionality in Javascript. It's meant to be the core component in any AJAX style framework. It is not an instantiable object, but instead is a namespaced microlibrary.

Calling is easy:
XMLRequest.GET(uri, query, callback, fallback)
uri: The location you're after
query: an associative array of form data to provide via the URL
callback: callback function of the form myCallbackFunction(objXMLHttpRequest), which is called upon successful (response = 200 OK) retrieval of the XML data
fallback: myFallbackFunction(objXMLHttpRequest), which is called upon failed (response != 200 OK) retrieval of the XML data.

XMLRequest.POST(uri, query, form, callback, fallback)
Similar, but does the query using the POST method. 'query' is the URL-appended data, still in associative array form, and 'form' is the same for the POST data.

Generates a tree view within a dropdown select box.

Simple chatting script to be placed on a corner of a website
Also a good example how to use ajax.

Set a word or phrase in an input field, clear it onfocus

I use this in my AJAX as a quick way to get the Value of the selected item in a Select HTML object. If nothing is selected, it returns zero.
(May be basic to y'all, but maybe really usefull to someone else).

ZeroField

AJAX: In situ edit
A simple edit in place using Prototype, based on the tutorial @ 24ways.org