SOURCE

function Person(){
    this.name = 'some person'
    this.age = 30
}

Person.prototype.SayHi = function(){
    console.log('hi, I am ' + this.name + ' , ' + this.age)
}

var p = new Person()
p.SayHi()

function Painter(){
    this.name = 'Painter'
}

Painter.prototype = new Person();

var pa = new Painter()
pa.SayHi()