Standard JS file structure

main.js

var MainScript = {
	init: function() {
		/**
		 * Init all Objects
		 */
		for (var n in this) {
			if ( typeof(this[n].init) === 'function' ){
				this[n].init();
			}
		}
	},
	siteWide: {
		init: function() {
			this.setListeners();
		},
		setListeners: function() {

		}
	},
	startPage: {
		init: function() {
			var isStartPage = document.querySelector('body.start');
			if(!isStartPage)
				return;
				
			this.setListeners();
		},
		setListeners: function() {
			
		}
	}
}
document.addEventListener("DOMContentLoaded", function() {
    MainScript.init();
});