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