gistfile1.js

var yao = {
  self: function () { return this }
}
console.log(yao === yao.self());

//yao.self is equal to yao, so this return a boolean value of true.

> var lebron = {
...   occupation: "basketball",
...   introduction: function () {
.....     return "My name is LeBron and I play " + this.occupation
.....   }
... }

undefined
> lebron.introduction();
'My name is LeBron and I play basketball'

//we can call this.occupation or lebron.occupation because lebron is the object

> var lebron = {
...   occupation: "basketball",
...   introduction: function () {
.....     return "My name is LeBron and I play " + lebron.occupation
.....   }
... }
undefined
> lebron.introduction();
'My name is LeBron and I play basketball'

var square = {
  side_length: 4,
  area: function () { 
    return this.side_length * this.side_length;
  }
}
console.log(square.area());

//this refers to the square object anywhere inside the object. Note that this is a standalone object.

var me = {
  first_name: "Matthew",
  last_name: "Powers",
  full_name: function () {
    return this.first_name + " " + this.last_name;
  }
}
console.log(me.full_name());

//again, this refers to the object.

circle.circumference = Math.PI * (circle.radius * circle.radius);
314.1592653589793

//set the standalone circle object's circumference method