Got to http://getfirebug.com an click the Install Firebug button, a few seconds later Firefox will show you a warning, accept with Install Now.
You can toggle Firebug with
F12 key. With Firebug you can now inspect the install button. Press
Ctrl-Shift-C and click the Install Firebug button. You should see this information about the button:
- the button is an
a-Element (anker), that points to https://getfirebug.com/downloads
- the styles of the button (color: #ffffff, etc.)
Most other web browsers come with similar development tools build in, but no one measures up to Firefox + Firebug in comfort and features.
There are several Firebug plugins for special web development purposes available, but for now the basic setup is just fine.