Colorizer is a free Firefox plugin that lets you change colors of HTML elements that are displayed on web pages. This is a great tool for web designers as they can quickly experiment on different color combination on a web page by trying different colors using Colorizer.
Colorizer is extremely simple to use. Just browse to any web page whose color you want to change. After that, start Colorizer plugin. Then, click on any HTML element on the screen whose color you want to change. After that, pick the new color for that HTML element from Colorizer. Colorizer will then reload the page, and show that HTML element with your selected colors. Isn’t it easy :)
Colorizer also lets you put multiple HTML elements in a group, and then change color of all the elements in a group together. This is helpful when you are trying to change text color for all HTML elements (like, H1, H2, paragraph, etc.). In this case, Colorizer will render all those HTML elements with your selected color.
Colorizer is extremely useful, and very easy to use. I believe this is the best Firefox plugin for developers, after Firebug.