毫秒倒计时：
<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script> </head> <body> <span id="minutesSpan"></span> 分 <span id="secondsSpan"></span> 秒 <span id="mSecondsSpan"></span>毫秒 <input type="button" value="开始" onclick="backTime()"> <span class="J_num">71</span> </body> </html> <script type="text/javascript"> var actionTime = localStorage.getItem('saveActionTime'); var data = new Date() var year = data.getFullYear(); var month = data.getMonth() + 1; var day = data.getDate(); if (actionTime) { var timeList = actionTime.split('-'); var oneStatus = year > timeList[0] var twoStatus = (year == timeList[0]) && (month > timeList[1]) var threeStatus = (year == timeList[0]) && (month == timeList[1]) && (day > timeList[2]) if (oneStatus || twoStatus || threeStatus) { localStorage.setItem('mSeconds', 59) localStorage.setItem('seconds', 59) localStorage.setItem('minutes', 1) localStorage.setItem('totalNum', 71) } } function backTime() { var mSeconds = localStorage.getItem('mSeconds') || 59; var seconds = localStorage.getItem('seconds') || 59; var minutes = localStorage.getItem('minutes') || 1; $('.J_num').text(localStorage.getItem('totalNum') || 71) var myTimer; myTimer = setInterval(function () { mSeconds--; if (mSeconds < 0) { seconds--; if (seconds < 0) { minutes--; if (minutes < 0) { clearInterval(myTimer); return; } else { seconds = 59; mSeconds = 99; } } else { mSeconds = 99; } } if (mSeconds % 200 == 1) { if (seconds % 2 == 1) { if ($('.J_num').text() > 10 || minutes != 0) { console.log(seconds) $('.J_num').text($('.J_num').text() - 1); console.log($('.J_num').text()) } } } localStorage.setItem('mSeconds', mSeconds) localStorage.setItem('seconds', seconds) localStorage.setItem('minutes', minutes) localStorage.setItem('totalNum', $('.J_num').text()) localStorage.setItem('saveActionTime', year + '-' + month + '-' + day) $("#mSecondsSpan").html(mSeconds < 10 ? "0" + mSeconds : mSeconds) ; $("#secondsSpan").html( seconds < 10 ? "0" + seconds : seconds); $("#minutesSpan").html(minutes < 10 ? "0" + minutes : minutes); }, 10); } </script>