Under Gmail's hood

Under Gmail's hood.

I'd been experimenting for a few months with Gmail, Google's Web mail
system, without really taking it seriously. But this week I decided to
take the plunge and try using Gmail not only as a mail search engine,
but as a replacement for Outlook (on Windows) and Mail (on OS X). Now
I'm ready to join the chorus singing the praises of GMail's
user-interface technology. Its combination of HTML, JavaScript, and the
DOM makes the browser do some remarkable tricks.


As early adopters discovered long before I did, there's an
architecture behind this JavaScript/DHTML wizardry. The best
description I've found is from Johnvey Hwang, who deconstructed Gmail's
JavaScript code and created a .Net-based Gmail API. As Hwang described
in his July 5 write-up, Gmail loads a JavaScript UI engine
into your browser at the beginning of each session. Oddpost, he noted,
was the first Web mail application to perfect this technique. That was
a prophetic statement: Just four days later, on July 9, Yahoo acquired
Oddpost.

Because Gmail's behavior is embedded in the UI engine, all
subsequent interaction between the browser and the Gmail service is
just an exchange of data. What Hwang calls the DataPack format is not
XML, though; it's JavaScript. When you make a request to the Gmail
service, whether to refresh your inbox or to modify the list of labels
you can attach to messages, the response is a minimal set of JavaScript
function calls and associated data objects that the engine uses to
update the display.

So is Gmail a rich Internet application? Sure. Although that label most
often applies to Java, .Net, and Flash clients, Gmail shows that Web
clients can join the club too. But crucially, Gmail's architecture is
open to other kinds of rich clients, too. It doesn't have to be a
zero-sum game. [Full story at InfoWorld.com]

[Jon's Radio]

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