定时器

1.倒计定时器(setTimeout)

var title = setTimeout(function() {
console.log('hehe');
clearTimeout(title);
},1000)

clearTimeout清除定时器
2.循环定时器(setInterval)

var title = setInterval(function(){
console.log('hehe');
clearInterval(title);
},1000);

cclearInterval清除定时器