How a Javascript beginner prepare the Test

All:

This is a half-technical question, as a beginner of Javascript developer, I do not have too much experience(did not get any training on standard software development procedure) about the whole development procedure. For my part, basically it is writting code and mannually find bug by running the code. Since it works for most time(my tasks are usually small, so I can maintain them manually), I have never paid a decent attention to how to do test in JS.

But recently I got asked a few times how do I do testing in JS dev, I feel there is nothing to say, so I am wondering if any one could give me some standard(or common procudure) ways about doing test in JS ?

An step by step example(from the first line of prototype to release product.) is more than appreciate.

Thanks