This plugin and the WorldWeather plugin are co-dependent. Check out the WorldWeather plugin for more information.
P.S. I really recommend getting a good text editor - or better yet, an IDE - when editing JS files. One free option is NotePad++, which offers basic syntax coloring, making comments, strings, and keywords stand out. This alone is a huge improvement over Windows's black-and-white Notepad. NotePad++ is just one; there's a ton out there. And I feel weird listing paid options by name, so I'll just say that there are also several good web-development-focused (including JS) IDEs out there. A few are free, but the best ones usually are not (though they often have one-month free trials). IDEs offer features like code-completion, jump-to-definition, and other things that make your life easier when programming.