how to understand JSBinding?

Hi, I’m new here.
I am focusing on the
common use of cocos2d-html5 & cocos2dx+jsbinding.
Now I just know about little except the importance of the “cocos2dx.cpp” and the “cocos2d_specifics.cpp”.
I will appreciate it if someone could tell me sth about how JSB works and how the function in the “cocos2dx.cpp” or “cocos2d_specifics.cpp” works as an example?
Thanks!