js inheritance

var Inheritance_Manager = {};

Inheritance_Manager.extend = function (subClass, baseClass) {
    function inheritance() { };
    inheritance.prototype = baseClass.prototype;
    subClass.prototype = new inheritance();
    subClass.prototype.constructor = subClass;
    subClass.baseConstructor = baseClass;
    subClass.superClass = baseClass.prototype;
}

function Human(age, grade){
  this.age = age;
  this.grade = grade
}

function Student(age, gender, grade){
  Student.baseConstructor.call(this, age, grade);
  this.gender = gender;
}

Inheritance_Manager.extend(Student, Human);