Google's New approach: Ajax

A new approach that is gaining in popularity among web developers is using XmlHttpRequest with Javascript.

This is not a new approach since XmlHttpRequest has been around for some time. What is new is that (a) it is being widely used by Google, and (b) a new name was coined for it recently.

Google Suggest

Google initially used XmlHttpRequest in Google Suggest. Just start typing slowly, and you will see that Google will query a huge list of words in real time and give you the matching words starting with what you typed. Yahoo Mail has also been using this for its email address lookup.

For a technical discussion on how this is done, someone dissected what is being done, and wrote a useful report.

What is also interesting is that Google must keep all these words in an in-memory cache. There is no room for disk access here. The results are displayed instantly.

Gmail

Google then moved on to use this combined XmlHttpRequest with Javascript in their excellent Gmail. Almost everything is done using this, and not entire page reloading. John Vey has a lot of info on the Gmail API. Some have even use this to build a GmailFS (Gmail File System) where they can store large files in their Gmail account(s).

Another article that dissected Gmail is John Udell's Under Gmail's hood. You can also read the Slashdot discussion.

Ajax is born

Although the technology has been around, a new name was coined for it recently: Ajax, short for Asynchronous Javascript + XML. Some have objected to this name as contrived, but it seems to have become widespread regardless.

Links on Ajax

• A video on how Ajax is used.
• More resources on Ajax.
• More on Ajax.