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<html lang="en"><head><meta charset="UTF-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge" /><meta name="viewport" content="width=device-width, initial-scale=1.0" /><title>Document</title><style>.countdown {width: 240px;height: 305px;text-align: center;line-height: 1;color: #fff;background-color: brown;/* background-size: 240px; *//* float: left; */overflow: hidden;}.countdown .next {font-size: 16px;margin: 25px 0 14px;}.countdown .title {font-size: 33px;}.countdown .tips {margin-top: 80px;font-size: 23px;}.countdown small {font-size: 17px;}.countdown .clock {width: 142px;margin: 18px auto 0;overflow: hidden;}.countdown .clock span,.countdown .clock i {display: block;text-align: center;line-height: 34px;font-size: 23px;float: left;}.countdown .clock span {width: 34px;height: 34px;border-radius: 2px;background-color: #303430;}.countdown .clock i {width: 20px;font-style: normal;}</style>
</head><body><div class="countdown"><p class="next">今天是2026年3月15日</p><p class="title">下班倒计时</p><p class="clock"><span id="hour">00</span><i>:</i><span id="minutes">25</span><i>:</i><span id="scond">20</span></p><p class="tips">18:30:00下课</p></div><script>// 函数封装function getCountTime() {// 1.得到当前时间戳const now = +new Date()// 2.得到未来时间戳const last = +new Date('2026-3-15 20:00:00')// 3.相减得到过程时间const count = (last - now) / 1000console.log(count)// 计算小时let h = parseInt(count / 60 / 60 % 24)h = h < 10 ? '0' + h : h// 计算分钟let m = parseInt(count / 60 % 60)m = m < 10 ? '0' + h : h// 计算当前秒数let s = parseInt(count % 60)s = s < 10 ? '0' + s : s// console.log(h, m, s)// 4.把分秒写到对应的盒子//# 是 CSS ID 选择器 的语法标记//#hour 表示：去页面里找 id="hour" 的那个 HTML 元素const hour = document.querySelector('#hour').innerHTML = hconst minutes = document.querySelector('#minutes').innerHTML = mconst scond = document.querySelector('#scond').innerHTML = s}// 先调用一次getCountTime()// 定时器setInterval(getCountTime, 1000)</script>
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