为了加强对JavaScript原生代码的编写能力，以及巩固setTimeout()的使用方法，制作了一个倒计时的demo，倒计时在现在的网站中算是一个常见的小功能，如果大家喜欢的话可以留下，就当作一个日常实用的小脚本。
实现思路
1、先获取小时值 将小时值减1开始进行倒计时 分钟59 秒数59
2、秒数的个位从9开始递减，当秒数个位小于0时，秒数的十位减1
3、秒数的十位小于0时，分钟的个位减1
4、分钟的个位小于0时，分钟的十位减1
5、分钟的十位小于0时，小时减1
6、小时数小于0后停止计时全部为0
实现代码
html
<p>倒计时：</p> <span id="hour">5</span> <span>:</span> <span id="minuteTen">0</span> <span id="minuteBit">0</span> <span>:</span> <span id="secondTen">0</span> <span id="secondBit">0</span>
css
span{
display: inline-block;
width: 20px;
height: 20px;
background-color: #000000;
color: #ffffff;
text-align: center;
}
JavaScript
function time(){
/*小时*/
var hourTxt = document.getElementById("hour");
var hour = parseInt(document.getElementById("hour").innerHTML);
/*分钟*/
var minuteTenTxt = document.getElementById("minuteTen");
var minuteBitTxt = document.getElementById("minuteBit");
var minuteTen = parseInt(document.getElementById("minuteTen").innerHTML);
var minuteBit = parseInt(document.getElementById("minuteBit").innerHTML);
/*秒*/
var secondTenTxt = document.getElementById("secondTen");
var secondBitTxt = document.getElementById("secondBit");
var secondTen = parseInt(document.getElementById("secondTen").innerHTML);
var secondBit = parseInt(document.getElementById("secondBit").innerHTML);
function start(){
hour--;
hourTxt.innerHTML = hour;
minuteTen = 5;
minuteTenTxt.innerHTML = minuteTen;
minuteBit = 9;
minuteBitTxt.innerHTML = minuteBit;
secondTen = 5;
secondTenTxt.innerHTML = secondTen;
secondBit = 9;
secondBitTxt.innerHTML = secondBit;
/*secondBit开始自减*/
function second(){
secondBit--;
secondBitTxt.innerHTML = secondBit;
/*十秒过后*/
if(secondBit < 0){
secondTen--;
secondTenTxt.innerHTML = secondTen;
secondBit = 9;
secondBitTxt.innerHTML = secondBit;
/*继续倒计时*/
setTimeout(second,1000);
/*一分钟过后*/
if(secondTen < 0){
minuteBit--;
minuteBitTxt.innerHTML = minuteBit;
secondTen = 5;
secondTenTxt.innerHTML = secondTen;
secondBit = 9;
secondBitTxt.innerHTML = secondBit;
/*十分钟过后*/
if(minuteBit < 0){
minuteTen--;
minuteTenTxt.innerHTML = minuteTen;
minuteBit = 9;
minuteBitTxt.innerHTML = minuteBit;
}
/*一个小时过后*/
if(minuteTen < 0){
hour--;
hourTxt.innerHTML = hour;
minuteTen = 5;
minuteTenTxt.innerHTML = minuteTen;
minuteBit = 9;
minuteBitTxt.innerHTML = minuteBit;
secondTen = 5;
secondTenTxt.innerHTML = secondTen;
secondBit = 9;
secondBitTxt.innerHTML = secondBit;
}
/*倒计时结束*/
if(hour < 0 ){
hour = 0;
hourTxt.innerHTML = hour;
minuteTen = 0;
minuteTenTxt.innerHTML = minuteTen;
minuteBit = 0;
minuteBitTxt.innerHTML = minuteBit;
secondTen = 0;
secondTenTxt.innerHTML = secondTen;
secondBit = 0;
secondBitTxt.innerHTML = secondBit;
clearTimeout(second);
clearTimeout(start);
}
}
}else{
setTimeout(second,1000);
}
}
setTimeout(second,1000);
}
setTimeout(start,1000);
}
执行页面
结束页面
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持Devmax。