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<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>继承</title>
<script type="text/javascript">
//继承 利用call 变量,缺点 无法继承 prototype 方法
var Parent = function () {
this.name = "parent";
this.array = [1, 2, 3];
}
Parent.prototype.say = function () {
console.log('hello');
}
var Child1 = function () {
Parent.call(this);
this.age = 18;
};
var c1 = new Child1();
console.log('c1', c1);
// 利用prototype 继承 ，缺点 实例化对象 无法数据 ，父类构造函数 实例化多次
var Child2 = function () {
this.age = 18;
}
Child2.prototype = new Parent();
var c2 = new Child2();
c2.array.push(4);
var c22 = new Child2();
console.log('c2', c2);
console.log('c22', c22);
//组合优化
var Child3 = function () {
Parent.call(this);
this.age = 18;
}
Child3.prototype = Object.create(Parent.prototype);
//解决 无法区分 是哪个类所实例化
Child3.prototype.constructor = Child3;
var c3 = new Child3();
c3.array.push(4);
var c33 = new Child3();
console.log('c3', c3);
console.log('c33', c33);
//c3.constructor==Child3.prototype.constructor
</script>
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<body>
</body>
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