css样式：

    <style>* {margin: 0;padding: 0;}p {font-size: 50px;text-align: center;}p span {color: orange;}p span.time {color: #4BAC3E;}body {padding-top: 200px;}</style>

html

    <p>距离2025年还有</p><p><span></span></p>

script

    <script>var oSpan = document.getElementsByTagName('span')[0];function tow(n) {return n >= 0 && n < 10 ? '0' + n : '' + n;}function getDate() {var oDate = new Date();//获取日期对象var oldTime = oDate.getTime();//现在距离1970年的毫秒数var newDate = new Date('2025/1/1 00:00:00');var newTime = newDate.getTime();//2021年距离1970年的毫秒数var second = Math.floor((newTime - oldTime) / 1000);//未来时间距离现在的秒数var day = Math.floor(second / 86400);//整数部分代表的是天；一天有24*60*60=86400秒 ；second = second % 86400;//余数代表剩下的秒数；var hour = Math.floor(second / 3600);//整数部分代表小时；second %= 3600; //余数代表 剩下的秒数var minute = Math.floor(second / 60);second %= 60;var str = tow(day) + '<span class="time">天</span>'+ tow(hour) + '<span class="time">小时</span>'+ tow(minute) + '<span class="time">分钟</span>'+ tow(second) + '<span class="time">秒</span>';oSpan.innerHTML = str;}getDate();setInterval(getDate, 1000);</script>