<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP ‘test3.jsp‘ starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script src="js/jquery-2.1.1.min.js"></script>
<script>
//obj.getPrototypeOf根据实例对象获得原型对象
function Person(){
}
Person.prototype.name=‘张三‘;
Person.prototype.age=‘21‘;
Person.prototype.sayName=function(){alert(thsi.name);}
var p1=new Person();
//alert(p1.name);
//var prototypeObj=Object.getPrototypeOf(p1);
//alert(prototypeObj===Person.prototype);
p1.name=‘王五‘;
//每次代码读取对象属性时，首先会进行一次搜索，搜索实例对象里name的属性，看看有没有，如果没有，
//然后再去p1的实例所对应的原型搜索，有就返回，没有返回undefined
//alert(p1.name);
//delete p1.name;
//alert(p1.name); //清除添加的name //获得原型对象的属性
//判断一个对象属性属于原型属性还是实例属性
var p3=new Person();
var s=p3.hasOwnProperty(‘name‘);
//alert(s); //false
p3.name=‘赵六‘;
//alert(p3.hasOwnProperty(‘name‘)); //true
//in操作符 判断属性是否存在于实例对象和原型对象(无法区分在实例还是原型)
var p4=new Person();
var p5=new Person();
//alert(‘name‘ in p4); //true
p5.name=‘旺旺‘;
//alert(‘name‘ in p5);
//在原型对象中是否存在属性
function hasOwnPrototypeBySelf(object,name){
return !object.hasOwnProperty(name) && name in object;
}
//alert(hasOwnPrototypeBySelf(p4,‘name‘)); //true
//alert(hasOwnPrototypeBySelf(p5,‘name‘)); //false
//Object.keys()拿到当前对象中所有的属性
var p6=new Person();
p6.sex=‘男‘;
//alert(Object.keys(p6));
//alert(Object.keys(Person.prototype));
//constructor属性，该属性不能被枚举出来
//Object.getOwnPropertyNames()获取所有属性 不关该属性是否可以被枚举
alert(Object.getOwnPropertyNames(Person.prototype));
</script>
</head>
<body>
This is my JSP page. <br>
</body>
</html>
时间： 2024-12-29 16:01:57