Generating code coverage for test cases is a handy feature, it gives you a quick and easy way to determine how much of your code is running during your tests. It doesn’t ensure that the tests are good or that you have enough assertions, but code that doesn’t run definitely has not been tested. Before code coverage was created it was very difficult to determine how much code was being run.

Events are the bread and butter of interactive websites. However, attaching and detaching events to the DOM can create memory leaks and performance issues due to time spent attaching events. This normally is not an issue, unless you are binding a large number of events.

If you’ve ever worked on a medium to large Ajax application, you know the headaches that Javascript can give you. On one hand you want to serve as few as possible Javascript files to users, but on the other you want to keep your sanity and work with lots of smaller files. This is where a build process comes in. It allows you to transform lots of files into one big file! You can even minify the big file for additional savings.