Unity for browser side scripting

Ok, so I have a website that requires unity to load the homepage. Doing that, I know everyone on subsequent pages has unity so I am doing a bit of my scripting through c# in unity, mostly stuff that can be done much easier using the System namespace in c#. I'm just putting the unity object in a div and hiding that.

My question: I need messaging between the unity object and the browser side javascript. I know I can send messages to the object through "SendMessage", but how do I receive the result of function calls through this?

There are some examples in the reference: Unity Web Player and browser communication