javascript 繼承 constructor 須要注意點

時間 2019-11-16

標籤 javascript 繼承 constructor 須要注意欄目 JavaScript 简体版

原文原文鏈接

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>

</body>
<script>
    var People = function(){
        this.name = "Jackey";
    };
    People.prototype.getName = function(){
        return this.name;
    };

    var Man = function(){
        this.sex = "male";
        People.call(this);
    };
    //缺點 ，name 是父類中的屬性，若是修改會影響子類
    //Man.prototype = People.prototype;
    //new 新開內存
    Man.prototype = new People();
    Man.prototype.constructor = Man;//可隨意修改People的屬性，不會影響到Man

    var man = new Man();
    console.log(man.getName());

</script>
</html>

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>

</body>
<script>
    var People = function(){
        this.name = "Jackey";
    };
    People.prototype.getName = function(){
        return this.name;
    };

    var Man = function(){
        this.sex = "male";
        People.call(this);
    };
    //缺點 ，name 是父類中的屬性，若是修改會影響子類
    //Man.prototype = People.prototype;
    //new 新開內存
    Man.prototype = new People();
    Man.prototype.constructor = Man;//可隨意修改People的屬性，不會影響到Man

    var man = new Man();
    console.log(man.getName());

</script>
</html>

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>

</body>
<script>
    var People = function(){
        this.name = "Jackey";
    };
    People.prototype.getName = function(){
        return this.name;
    };

    var Man = function(){
        this.sex = "male";
        People.call(this);
    };
    //缺點 ，name 是父類中的屬性，若是修改會影響子類
    //Man.prototype = People.prototype;
    //new 新開內存
    Man.prototype = new People();
    Man.prototype.constructor = Man;//可隨意修改People的屬性，不會影響到Man

    var man = new Man();
    console.log(man.getName());

</script>
</html>

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