More information and a summary report
When you hover over an element with an inline event, it will show you more information about it:
The same goes for
At the bottom left corner of the window, you will be presented with a summary report of the number of
It is available as a Firefox extension, Greasemonkey user script, as well as a Ubiquity command. The Greasemonkey user script can be customized to only work for certain domains (default is all domains).