*{margin:0px;padding:0px;}
#box{width:200px;height:50px;background:green;color:white;text-align:center;font:bold 30px/50px 黑体; margin:0px auto;}
10
//找对象
var box = document.getElementById('box');
//alert(box);
//alert(box.innerHTML);
//box.innerHTML ='为什么这么衰';
//初始化的值
var num = box.innerHTML;
//改属性
var timmer = setInterval(function(){
num--;
console.log(num);
//把num 的值赋值给div元素的对象的文本值
box.innerHTML = num;
if(num == 0){
//清除定时器
clearInterval(timmer);
alert('倒计时结束');
}
},1000)
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "https://hm.baidu.com/hm.js?f84e07df8353f7596cb357b2195828a7";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();