delete 用法

1、对象属性的删除

function fun(){
 
this.name = 'mm';
 
}
 
var obj = new fun();
 
console.log(obj.name);//mm
 
delete obj.name;
 
console.log(obj.name); //undefined

2、变量不能删除

var name = 'lily';

delete name;

console.log(name); //lily

 

3、删除不了原型链中的变量

fun.prototype.age = 18;

delete obj.age;

console.log(obj.age) //18