这又是ES6 JS高级Es6语法

  let a;let b,c,d;let f=567,g="liveyou",h=[];

 {let  gair="李四"// console.log(gair)}
console.log(gair)

 console.log(aaa)var aaa="先鸟"；let aaa="先鸟"

 {let school="上高速"function fn(){console.log(school)}fn()}

   const SCHOOL = "我要上高速"const TEAM = ['UZR', 'MXLG', 'MING', 'LETME'];// TEAM.push('Meiko')console.log(TEAM)

 <!-- 数组解构--><!--! ES6按照一定的模式从数组对象中提取值 对变量赋值  这被称为解构赋值--><!-- !数组结构 --><script>const F4=['A','B','C','D','E']let [a,b,c,d,e]=F4console.log(a+b+c+d+e)</script><!-- !对象的结构 --><script>const zhaomienan={name:"静态",age:'89',eat:function(){console.log("吃饭")},sleep:function(){console.log("睡觉吧")}};let {name,age,eat,sleep}=zhaomienan;console.log(name+"_"+age+"_"+eat+"_"+sleep)eat()sleep()</script>

  // 声明let str=`我是字符串的内容解析`console.log(str,typeof str)// 内容直接有换行符let str1=`<ul><li>1</li><li>2</li><li>3</li></ul>`// document.write(str1)// 变量的直接拼接let lover='上述'let out=`${lover}是我心中的偶像`console.log(out)

 <script>let name = "李四玩有幸"let change = function () {console.log("我可以改变你的内容信息")}const school = {// name:namename,change,imporve: function () {console.log("我深蓝了")},eat() {console.log("Hellow word")}}console.log(school)</script>

 <script>let fn = function () {}let fn1 = (a, b) => {return a + b;}let results = fn1(1, 1)console.log(results)// 箭头函数 // 1 this 是静态的  始终指向函数声明的作用域下的this 的值function getName() {console.log(this.name)}let getName2 = () => {console.log(this.name)}// 设置Window对象window.name = '加油'const school = {name: "ASDFGHJ"}// 直接调用// getName()// getName2()// call 方法的调用  改变this的值getName.call(school)getName2.call(school)// 2 不能作为构造函数 实例化对象// let Person=(name,age)=>{// this.name=name;// this.age=age;// }// let me=new Person("销毁",90);// console.log(me)// 3 不能使用arguments对象// let fn23=()=>{// console.log(arguments)// }// fn23(1.2,3)// 4 箭头函数的简写      省略()有且只有一个let add=n=>{return n+n;}console.log(add(9))// 省略{}  returnlet pow =(n)=>n*nconsole.log(pow(9))</script>

 // 形参的初始值// function add(a,b,c,d,e){// return a+b+c+d+e;// }// let result=add(1,2,3,4);// console.log(result)// 与结果赋值使用function connect(host = "127.0.9.0", username, password, port) {console.log(host)}connect({host: "123456",username: "李四上栅",password: "12345678",port: "33060987"})// ES5function date1() {console.log(arguments)}date1("1张三", "2李四", "3空", "4思考", "5小康", "6订单")// rest 参数 必须放在最后 这是为什么?function date(...args) {console.log(args)}date("1张三", "2李四", "3空", "4思考", "5小康", "6订单")function fn4(a, b, c, d, e, f, ...args) {console.log(a);console.log(b);console.log(c);console.log(d);console.log(e);console.log(f);console.log(args);}fn4("1张三", "2李四", "3空", "4思考", "5小康", "6订单","47思考", "58小康", "69订单","4思考", "5小康", "6订单")

  <script>const tyop=['XXX','YYY','RRR','HHH','LLL','WWW','DDD','FFF','SSS']function chunwan(){console.log(arguments)}chunwan(...tyop)</script><script>//定义一个集合let arrayLike = {'0': 'a','1': 'b','2': 'c',length: 3}; //转成数组let arr2 = Array.from(arrayLike); // ['a', 'b', 'c']console.log((arr2))</script>

 <!-- 扩展运算符的应用 --><div></div><div></div><div></div><!--! 数组的并和 亲生 误删 唐安 --><script>const kuaizi=['效率','小明',"小王","小鸡"]const fangkuang=['小坡','老婆','欧赔']constfangkuang1=kuaizi.concat(fangkuang)// ES5console.log(constfangkuang1)// ES6const hebing=[...kuaizi,...fangkuang]console.log(hebing)// 数组克隆const san=['A','B','C']const sane=[...san]console.log(sane)// 3 将伪数组转为真正的数组const divs=document.querySelectorAll("div");const divArr=[...divs];console.log(divArr)</script>