Maintaining websites is a task made difficult by huge CSS definition lists. It used to take quite some time to figure out how a group of CSS definitions interacted with a certain section of a website and to identify what bit of CSS to change for a desired effect to be seen on a website.
That was some time ago. Now we have a highly useful plugin for Firefox called “Firebug”. After installing Firebug, just look at any webpage using Firefox and right click anywhere on the webpage to click on an “Inspect Element” option that shows up. Voila! You get a Firebug interface that shows you the code around the area you clicked and the CSS that is reponsible for styling that bit of code that you clicked on.Along with the CSS definitions that are applicable to the area under consideration, you get to know the line number of the CSS code.
This functionality saves substantial time in updating CSS definitions or any JavaScript on a web page. I recommend this free product to any web developer.