Hacking Gmail

Part II — Getting Inside Gmail
Once you’ve downloaded the applications, you can start. Figure 4-1 shows my
own Gmail Inbox with a single message inside.
The first thing to do is open up Firefox’s DOM inspector, which tells you what
the browser itself is seeing. Half expanded, it looks like Figure 4-2.
The figure shows you that the application is made up of a single document (obvi-
ously), containing a frameset and some markup. That tiny amount of markup,
shown in Figure 4-2 as the NOSCRIPT section, is simply a message that displays
only if you’re trying to look at Gmail with JavaScript turned off, telling you that
you’re out of luck without JavaScript. The frameset is where it’s at. It contains two
frames, the first of which has 12 divs in its body, while the second frame has a
large script element, but nothing of note in the body. Further exploration, not
shown here, will point out that the second frame contains a vast amount of
JavaScript and nothing else. That, as you will see in later chapters, makes up the
real client-side workings of Gmail. For your purposes now, however, you can con-
centrate on the first frame.
So, working with the first frame, you see it is made up of 12 divs, each with its
own class name, as illustrated in Figure 4-3.