一、计时器

css样式

<button class='btn1'>停止一次性定时器</button>
<button class='btn2'>停止永久性定时器</button>
script 一次性定时器

var btn1=document.querySelector('.btn1');
var btn2=document.querySelector('.btn2');
function show(){
console.log('这是一次性定时器');
}//一次性定时器
script 永久性定时器

var timer=setTimeout(show,3000);
btn1.onclick=function(){
clearTimeout(timer);
}

function print(){
console.log('这是永久性定时器');
}
var times=setInterval(print,1000);
btn2.onclick=function(){
clearTimeout(times);
}
二、instanceof

var arr=[1,2,3,4,5];
var obj={name:'jack'};
console.log(arr instanceof Array);
console.log(obj instanceof Array);
三、深度克隆

var student={
name:'jack',
age:18,
friend:['lily','lucy']
}
function clone(obj){
var newObj=obj instanceof Array?[]:{};
for(var key in obj){
if(obj[key] instanceof Object){
newObj[key]=clone(obj[key]);
}else{
newObj[key]=obj[key];
}
}
return newObj;
}

var newObj=clone(student);
student.friend[0]='rose';
console.log(student.friend[0]);
console.log(newObj.friend[0]);