This is a snippet of a nice introducing modules to your js code.

JS module (AMD & standard)

(function (factory) {
  if (typeof define === 'function' && define.amd) {
		// AMD is found. Use it to register as anonymous module.
		define(['jquery'], factory);
	} else {
		// AMD is not found, use a standard module patter
		factory(jQuery);
	}
}(function ($) {
  // use $ safetly, it's provided either by AMD or a simple module patter
}));