How to design a large JavaScript Application [on hold]

I am searching for solutions how to design a "large" javascript application.

I tried to draw the cross relations, which I will need: http://ift.tt/1WxZg1w

I have a fix template of the App and dynamic content, like site1. The App is connected via Websocket to a server and I have a lot of cross realtions of vars as you can see in the drawing.

My question is now: How to design and split up the party in a nice way. How can I react on events in the application, so for example change the JS value of vars inside the "site1 widget" and the other way.. how to send for example x/y via the websocket to the server..

Thank you very much :)