var obj={
	name: 'zhagnsan',
	age: 19 
}
delete obj.name //true
typeof obj.name //undefined

var name ='zs' //已声明的变量
delete name //false
console.log(typeof name) //String

age = 19 //未声明的变量
delete age	 //true
typeof age //undefined

this.val = 'fds' //window下的变量
delete this.val	 //true
console.log(typeof this.val) //undefined

var fn = function(){} //已声明的函数
delete fn	//false
console.log(typeof fn) //function

fn = function(){} //未声明的函数
delete fn	//true
console.log(typeof fn) //undefined

var arr = ['1','2','3'] ///已声明的数组
delete arr //false
console.log(typeof arr) //object

arr = ['1','2','3'] //未声明的数组
delete arr //true 
console.log(typeof arr) //undefined

var arr = ['1','2','3'] //已声明的数组
delete arr[1] //true
console.log(arr) //['1','empty','3'] 

var person = {
 height: 180,
 long: 180,
 weight: 180,
 hobby: {
  ball: 'good',
  music: 'nice'
 }
}
delete person ///false
console.log(typeof person)  //object

var person = {
 height: 180,
 long: 180,
 weight: 180,
 hobby: {
  ball: 'good',
  music: 'nice'
 }
}
delete person.hobby ///true
console.log(typeof person.hobby) //undefined