If you make web pages, you’ll soon be unable to live without Mozilla‘s DOM Inspector. No, don’t leave now! Even if the word “DOM” scares you, you’ll still like the Inspector. [Win moz users: try hitting ctrl+shift+i right now.]
Imagine something which allows you to click on a part of your page and see the code which produces it, select any tag or entity and see exactly which CSS styles are applied, or which JavaScript calls it. Wouldn’t that be great for debugging? Read more about the DOM Inspector, you’ll love it!
It is indeed very useful. Before it, I would always use flashy colors and
borders for my CSS layouts to find where each thing was while I was
positionning elements, and now I can just use the DOM Inspector.
Very annoying that I have to go back to the flashy colors trick when I
have to test what it gives on other, inferior browsers.