Use javascript MVC Framework in order to organize the javascript code in a standard way.
Best JavaScript MVC frameworks available are:
- Backbone
- Angular
- CanJS
- Ember
- ReactJS
Selecting a JavaScript MVC framework required so many factors to consider. Read the following comparison article that will help you to select best framework based on the factors important for your project:
http://sporto.github.io/blog/2013/04/12/comparison-angular-backbone-can-ember/
You can also use RequireJS with the framework to support Asynchrounous js file & module loading.
Look the below to get started on JS Module loading:
http://www.sitepoint.com/understanding-requirejs-for-effective-javascript-module-loading/