The beginnings of Ajax as used today started with the release of
Internet Explorer 5 in 1999, which introduced a new ActiveX object,
XMLHttpRequest. ActiveX is
Microsoft’s technology for signing plug-ins that add additional software
to your computer. Other browser developers later followed suit, but
rather than using ActiveX, they all implemented the feature as a native
However, even before then, an early form of Ajax had already surfaced that used hidden frames on a page that interacted with the server in the background. Chat rooms were early adopters of this technology, using it to poll for and display new message posts without requiring page reloads.
XMLHttpRequest is the way to go, and there
have been numerous frameworks written to simplify its use. In fact,
Chapter 19 introduces the powerful
what your program and the browser are doing as you code with YUI or
another library of your choice.