javascript当中的构造函数的用法

5)构造函数的用法:

例 3.5.1

<head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
</head>
<script>
    function Student(name, age)
    {
        /* 马克-to-win:later on we can use it in
        var doc = new ActiveXObject( "Microsoft.XMLDOM" );
                    doc.async="false";
                    doc.load(str);
        when a property has a this, means that this property is a member property.
        */
        this.name = name;
        this.age = age;
        this.parti = function()
        {
            document.writeln("名字是:" + this.name + "<br>");
            document.writeln("年纪是:" + this.age + "<br>");
        };
    }
    var p = new Student('jeri', 3);
    document.writeln("typeof p is " + typeof(p));
    //typeof(p) is object
    p.parti();
    p.age = 4;
    p.parti();
    /*the following two methods can also access some properties.*/
    document.writeln("" + p["age"]);
    document.writeln("" + p["a" + "ge"]);


    if (p instanceof Student) document.writeln("p是Student的实例<br>");
    /*javascript 中的对象全部是Object 的子类
    Because this object is the topmost parent object in the prototype inheritance hierarchy, all other object classes inherit its methods and properties. It's a close enough call that JavaScript 2.0 may well move it into the class-based object-oriented category at which time the prototype inheritance would be replaced with super-class/sub-class mechanisms and the arguments become null and void.  */
    /*When the Global object is created, it always has at least the following properties:
       Object object
       Function object
       Array object
       String object
       Boolean object
       Number object
       Date object
       Math object
       Value properties
   */
    if (p instanceof Object) document.writeln("p是Object的实例");
</script>

文章转载自:https://blog.csdn.net/qq_44594249/article/details/100032253

posted @ 2020-01-10 16:18  盖世神功  阅读(465)  评论(0编辑  收藏  举报