this in Js

app.js

// This is like a parameter to a function and it depends on the value binded to it.
// Binding of value to 'this' is comptely taken care by language.
// The calling object of the function is binded to "this".

var obj = {
  method: function (){
    console.log(this);
  },
  param:'value'
};

obj.method();

// here the method logs obj .
//hence calling object of the function reffered to this inside function.
// so, key here for 'this' is '.' , to the left of which obj is binded to "this" in case of calling the method.