How does GMail display the sidebar?

You know, like the "Compose Mail," "Inbox," "Sent Mail," etc., on the left hand-side when you load up GMail? I did a s开发者_C百科earch for "Compose Mail" in the page source and got nothing.

The Gmail interface uses JavaScript to dynamically load a lot of stuff. That explains why you don't see "Compose Mail".

If you want to see how the final HTML document looks like, then here is my method:

It's all Javascript. Here's how you can get at that information yourself: if you don't already use Firefox, download it, and then install the Firebug extension. Among other features, it'll let you click on any component of the page and show you the corresponding location in the source - not just the original page source, but the source after all the Javascript has taken effect.

Actually, if you use Internet Explorer, the IE Developer Toolbar (included in IE 8) does something similar, although I haven't used it much myself.