js 判断存在于原型中的属性

ptspzy

于 2016-06-16 21:09:03 发布

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分类专栏： javascript 文章标签： javascript

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<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<script>
    function Person() {
    }

    Person.prototype.name="Nicholas";
    Person.prototype.age=29;
    Person.prototype.sayName=function(){
        alert(this.name);
    }

    var person1=new Person();
    person1.name="Greg";

    var person2=new Person();

console.log(person1.hasOwnProperty("name"));//true
console.log(person2.hasOwnProperty("name"));//false

console.log("name" in person1);//true
console.log("name" in person2);//true

for (var prop in person1) {
    console.log(prop);//name   age   sayName
}

function hasPrototypeProperty(object,pro) {//如此可判断存在于原型中的属性
    return (!object.hasOwnProperty(pro))&&(pro in object);
}
console.log(hasPrototypeProperty(person1,"name"));//false
console.log(hasPrototypeProperty(person2,"name"));//true
</script>
<body>

</body>
</html>