Access object properties and methods
Accessing the properties of an object
In JavaScript, you can use "." and "[]" to access the properties of an object.
1. Use "." to access object properties
Syntax:
objectName.propertyName
Where objectName is the object name and propertyName is the property name.
2. Use "[ ]" to access object properties
Syntax:
objectName[propertyName]
Where objectName is the object name and propertyName is the property name.
Methods to access objects
In JavaScript, you can only use "." to access methods of objects.
Syntax:
objectName.methodName()
Among them, objectName is the object name and methodName() is the function name.
Example: Create a Person class:
<html>
<head>
<script>
function Person() {
this.name=" 张三 "; // 定义一个属性 name
this.sex=" 男 "; // 定义一个属性 sex
this.age=22; // 定义一个属性 age
this.say=function(){ // 定义一个方法 say()
return "嗨！大家好，我的名字是 " + this.name + " ，性别是 " + this.sex + "，今年 " + this.age +"岁！";
}
}
var zhangsan=new Person();
alert("姓名："+zhangsan.name); // 使用“.”来访问对象属性
alert("性别："+zhangsan.sex);
alert("年龄："+zhangsan["age"]); // 使用“[ ]”来访问对象属性
alert(zhangsan.say()); // 使用“.”来访问对象方法
</script>
</head>
<body>
</body>
</html>
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