It only actually tells users how to run JS code on page 311, where users are told of the following solutions:
Inline, between a pair of <script> and </script> tags
From an external file specified by the src attribute of a <script> tag
In an HTML event handler attribute, such as onclick or onmouseover
I was wondering what professional JS developers use to write and test their code: Do they use a good text editor with syntax high-lighting + autocompletion, hit F5 in the browser to reload the page every time they make a change, and use some add-on in the browser to investigate errors? Or are there full-fledged IDE's similar to MS VisualStudio for non-web languages?
Edit: For instance, I wrote this piece of code, which doesn't work (nothing displayed on screen when calling index.html), but Firefox doesn't display any error. How would I go trying to understand why it's not working?