<span>00:01:11:00</span> <input type="button" value="start countdown!"> <input type="button" value="stop countdown!"> <br> <input type="text"> <input type="text"> <script language="Javascript"> var normalelapse = 100; var nextelapse = normalelapse; var counter; var startTime; var start = clock.innerText; var finish = "00:00:00:00"; var timer = null; // 开始运行 function run() { startB.disabled = true; endB.disabled = false; counter = 0; // 初始化开始时间 startTime = new Date().valueOf(); // nextelapse是定时时间, 初始时为100毫秒 // 注意setInterval函数: 时间逝去nextelapse(毫秒)后, onTimer才开始执行 timer = window.setInterval("onTimer()", nextelapse); } // 停止运行 function stop() { startB.disabled = false; endB.disabled = true; window.clearTimeout(timer); } window.onload = function() { endB.disabled = true; } // 倒计时函数 function onTimer() { if (start == finish) { window.clearInterval(timer); alert("time is up!"); return; } var hms = new String(start).split(":"); var ms = new Number(hms[3]); var s = new Number(hms[2]); var m = new Number(hms[1]); var h = new Number(hms[0]); ms -= 10; if (ms < 0) { ms = 90; s -= 1; if (s < 0) { s = 59; m -= 1; } if (m < 0) { m = 59; h -= 1; } } var ms = ms < 10 ? ("0" + ms) : ms; var ss = s < 10 ? ("0" + s) : s; var sm = m < 10 ? ("0" + m) : m; var sh = h < 10 ? ("0" + h) : h; start = sh + ":" + sm + ":" + ss + ":" + ms; clock.innerText = start; // 清除上一次的定时器 window.clearInterval(timer); // 自校验系统时间得到时间差, 并由此得到下次所启动的新定时器的时间nextelapse counter++; var counterSecs = counter * 100; var elapseSecs = new Date().valueOf() - startTime; var diffSecs = counterSecs - elapseSecs; nextelapse = normalelapse + diffSecs; diff.value = counterSecs + "-" + elapseSecs + "=" + diffSecs; next.value = "nextelapse = " + nextelapse; if (nextelapse < 0) nextelapse = 0; // 启动新的定时器 timer = window.setInterval("onTimer()", nextelapse); } </script>
PS：这里再为大家推荐几款时间及计时器相关工具供大家参考使用：
更多关于JavaScript相关内容感兴趣的读者可查看本站专题：《JavaScript时间与日期操作技巧总结》《JavaScript错误与调试技巧总结》、《JavaScript数据结构与算法技巧总结》、《JavaScript遍历算法与技巧总结》及《JavaScript数学运算用法总结》