example.js

function Person(name) {
  this.name = name;
}

Person.prototype.greet = function() {
  console.log("Hello, my name is" + this.name);
}


// as of 2015...
class Person {
  constructor(name){
    this.name = name;
  }
  greet() {
    console.log("Hello, my name is" + this.name);
  }
}