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()