JS 对象的继承

//定义父元素
function Animal(name,kg){
    this.name = name;
    this.kg = kg;
};
Animal.prototype.say = function(){
    alert('大家好-',this.name);
}
//子元素
function Dog(type){
    this.type = type;
}
Dog.prototype.job = function(){
    alert('我的种类是'+this.type+',专门看家')
}
//继承
var extend = function(sub,sup,q,w){
    var objSup = new sup(q,w);
    sub.apply(sup);
    sub.prototype = Object.assign(sup.prototype,sub.prototype);
    sub.prototype.constructor = sub;
}
extend(Dog,Animal,'a','b');
var taidi = new Dog('泰迪');
console.log(taidi)
taidi.job();
taidi.say()