JavaScript使用setTimeout实现倒计时效果

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592、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13、秒数的十位小于0时，分钟的个位减14、分钟的个位小于0时，分钟的十位减15、分钟的十位小于0时，小时减16、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

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