js delete 用法

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