I want to tell you about Firefox and its related features to web development. The first thing is multiple profiles. As a web developer, you should install so many Firefox Addons. This yields to a heavy browser that is not so nice. My suggestion is having a profile for web surfing and a profile for web development.
How to create multiple profiles?
Run this command in your Run window: "
firefox -profilemanager -no-remote"

This window will appear:

now create a new profile and press Exit:

now run this command: "
firefox -p sample -no-remote" sample is the name of your profile

Firefox will start with the new profile. So you can install and test Addons before using them.