Not too long ago I was shown a Firefox plug-in by a fellow worker that has proved itself to be extremely useful and saved a lot of time in website development.
This add-on is called the web developer tool bar and I recommend it for any one involved in building websites, from the designers to the programmers to anyone who puts websites together. I honestly have not even cracked the surface of exploring all of the features that this plug-in provides, but the ones I have used are a big help.
My favorite use as a programmer is when I am testing my ColdFusion forms. There is an option to populate form fields that automatically fills in all of the form fields. Manually filling in fields during numerous form tests gets monotonous and is a waste of time, but this function can do it in a flash. This function alone is what made me a user for life.
Other functions provided deal with all aspects of your page. You can get detailed information on any images, validate content, work with CSS style sheets, alter cookies, set window size, highlight the outlines of the tables on your page, and so much more. If you’re in any area of web development, do yourself a favor and download the web developer tool bar for Firefox.