1,对象属性删除
function fun(){
this.name = 'mm';
}
var obj = new fun();
console.log(obj.name);//mm
delete obj.name;
console.log(obj.name); //undefined
2,变量删除
var name = 'lily';
delete name;
console.log(name); //lily
直接用delelte删除不了变量
3,删除不了原型链中的变量
fun.prototype.age = 18;
delete obj.age;
console.log(obj.age) //18