utilities.js contains functions used by various other scripts,
primarily in order to handle cross-browser compatibility issues
easier. Currently in order to give my scripts access to those utility
functions, I need to include utilities.js from within the HTML. I
would like to instead include utilities.js from within the script
which actually relies on utilities.js. Essentially, I am looking for a
javascript equivalent of PHP's include() function. It must work in all
browsers.