JavaScript学习笔记三：JavaScript对象

浏览数：20 / 时间：2015年06月08日

一、前言

对象的基本概念：Javascript提供了多个内建对象，比如String、Data、Array等等。对象指的是带有属性和方法的特殊数据类型
创建对象：创建JavaScript对象主要有两种不同的方法：第一、定义创建对象的实例；第二，使用函数来定义对象，然后创建新的对象

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
</head>
<body>
<script>
    //创建直接的实例
    persion = new Object();
    persion.firstname = "Bill";
    persion.lastname = "Gates";
    persion.age = 56;
    persion.eyecolor = "blue";
    document.write(persion.firstname + " is " + persion.age + " years old.<br/>");
    //替代语法（使用对象literals）
    persion = {firstname:"John",lastname:"Doe",age:50,eyecolor:"blue"};
    document.write(persion.firstname + " is " + persion.age + " years old.<br/>");
    //使用构造器构造对象
    function persionV(firstname,lastname,age,eyecolor){
        this.firstname = firstname;
        this.lastname = lastname;
        this.age = age;
        this.eyecolor = eyecolor;
        //将方法添加到JavaScript对象中
        this.changeName = changeName;
        function changeName(name){
            this.lastname = name;
        }


    }
    myFather =  new persionV("Bill","GateV1",89,"red");
    document.write(myFather.firstname + " is " + myFather.age + " years old.<br/>");
    myFather.changeName("hehehe");
    document.write(myFather.firstname + " " + myFather.lastname + " is " + myFather.age + " years old.<br/>");
</script>
</body>
</html>

访问对象的属性，属性指的是与对象相关的值，访问对象属性的语法如下：
```
objectName.propertyName
```
具体例子：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
</head>
<body>
<script>
    var message = "Hello World!";
    var x = message.length;
    document.write(x)
</script>
</body>
</html>

访问对象的方法：方法指的是能够在对象上执行的动作，具体语法如下：
```
objectName.methodName()
```
具体例子：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
</head>
<body>
<script>
    var message = "Hello World!";
    var x = message.toUpperCase();
    document.write(x)
</script>
</body>
</html>