September 26th, 2004

amused, silly, ha ha only serious

Those Google guys are clever...

You've probably noticed that Gmail's interface is extremely fast when compared to other web-based email systems like Yahoo! Mail and Hotmail. This is a result of Gmail's placement of the UI engine on the client-side as a JavaScript module. Whenever you log in to Gmail, a copy of the UI engine is loaded into one of the HTML page frames and remains there for the duration of your session. Subsequent actions from the Gmail interface are then routed through the Gmail UI engine in your browser, which in turn makes HTTP requests to the Gmail server, interprets the DataPack (more on this later), and updates the UI dynamically. In contrast, Hotmail and Yahoo! Mail follow traditional web application models and reload the entire UI after almost every action.
That's a bit thick on the technical stuff, but basically what it comes down to is this.

Normal Site: Sends code with the data embedded in it each time you access a page.

Gmail: Sends all the code first, then sends only the data each time you access a page.

Damn clever--and it means that Gmail's pretty easy to screen-scrape.

(From John Vey's site.)