## 1.Math
~~~
Math.ceil()
Math.floor()
Math.round()
Math.random()
Math.max()
Math.min()
~~~
## 2.Date
~~~
//获取当前时间
var oDate = new Date();
var year = oDate.getFullYear();
var month = oDate.getMonth();
var date = oDate.getDate();
var hour = oDate.getHours();
var minute = oDate.getMinutes();
var second = oDate.getSeconds();
var mill = oDate.getTime();
~~~
~~~
//月份从0开始
var month = oDate.getMonth()+1;
//星期从0开始，0表示星期天
//0,1,2,3,4,5,6
var day = oDate.getDay();
~~~
leg:实现一个数码时钟
* 思路
* [ ] 获取系统时间
* [ ] Date对象
* [ ] getHours,getMinutes,getSeconds
* [ ] 显示系统时间
* [ ] 字符串连接
* [ ] 小于10补零
* [ ] 使用定时器 setInterval()
~~~
//HTML
<div id="clock">
<img src="images/0.png" alt="">
<img src="images/0.png" alt="">
<img src="images/0.png" alt="">
<img src="images/0.png" alt="">
<img src="images/0.png" alt="">
<img src="images/0.png" alt="">
</div>
showTime();
setInterval(showTime,1000)
function showTime() {
var d = new Date();
var hour = d.getHours();
var minute = d.getMinutes();
var second = d.getSeconds();
//1.小10补零
function add(time) {
if (time < 10) {
return "0" + time
} else {
return time + "";
}
}
var allTime = add(hour) + add(minute) + add(second);
//2.分割字符串显示系统时间
var arr = allTime.split("");
console.log(arr);
var imgs = document.getElementsByTagName("img");
for (let i = 0; i < imgs.length; i++) {
imgs[i].src = "images/" + arr[i] + ".png"
}
}
~~~
