Quick Lesson On Using Terminal on Mac
Sublime Text, Sublimelinter and JShint
If you want to quickly grab JavaScript errors, you want to use JSHint. If you are using Sublime Text as your editor, there are a few steps involved. Here is a short video that quickly shows you how to get up and running with JSHint.
Quickly set up server to work with AJAX (video)
You need a server for AJAX and instead of using something like MAMP this is a much easier, lightweight way.