1,對象屬性刪除

function fun(){

this.name = 'mm';

}

var obj = new fun();

console.log(obj.name);//mm

delete obj.name;

console.log(obj.name); //undefined

2,變量刪除

var name = 'lily';
delete name;
console.log(name); //lily

直接用delelte刪除不了變量
3,刪除不了原型鏈中的變量

fun.prototype.age = 18;
delete obj.age;
console.log(obj.age) //18