prototypal inheritance - Javascript call the base class constructor -

person base class , emp inherits person. trying use name, location properties of person in emp.

function person(name, location){    this.name = name;    this.location = location; }  person.prototype.getname = function(){    return 'name: ' + this.name; }  function emp(id, name, location){      this.id = id;      person.call(this, name);      person.call(this, location); }  emp.prototype = object.create(person.prototype);  var e1 = new emp(1, 'john', 'london'); e1.id   // 1 e1.name // 'london' e1.location //undefined 

what causing error , why name taking value of london?

why calling constructor twice single argument?

function emp(id, name, location){      this.id = id;      person.call(this, name, location); }