关于 JS 中的继承的奇葩问题

function superClass(name, age){
    this.name = name;
    this.age = age;
    this.test = "1111"
}

superClass.prototype = {
    consturct: superClass,
    init: function () {
        console.log("this is superClass init");
    }
}

function subClass (name, age, job) {
    superClass.call(this, name, age);
    this.job = job;
    this.test = "22222";
}

subClass.prototype = new superClass();
subClass.prototype.init = function init () {
    console.log(this.job);
}

var s = new superClass("zhanghao", 22);
console.log(s.test); // "1111"
s.test = "wo gai le a";
console.log(s.test); // "wo gai le a"

delete(s.test);
console.log(s.test); // undefined

var ss = new subClass("haha", 22, "av nan you");
console.log(ss.test); // "22222"
ss.test = "qtmlgb";
console.log(ss.test); // qtmlgb

delete(ss.test)
console.log(ss.test); // "1111"

delete(ss.test);
console.log(ss.test); // "1111"