<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>js简单时分秒倒计时</title> <script type="text/javascript"> function countTime() { var timer; //获取当前时间 var date = new Date(); var now = date.getTime(); //设置截止时间 var str = "2020/2/8 15:40:00"; var endDate = new Date(str); var end = endDate.getTime(); //时间差 var leftTime = end - now; //定义变量 d,h,m,s保存倒计时的时间 var d, h, m, s; if (leftTime >= 0) { d = Math.floor(leftTime / 1000 / 60 / 60 / 24); h = Math.floor(leftTime / 1000 / 60 / 60 % 24); m = Math.floor(leftTime / 1000 / 60 % 60); s = Math.floor(leftTime / 1000 % 60); //将倒计时赋值到div中 document.getElementById("_d").innerHTML = d + "天"; document.getElementById("_h").innerHTML = h + "时"; document.getElementById("_m").innerHTML = m + "分"; document.getElementById("_s").innerHTML = s + "秒"; } else { //将倒计时赋值到div中 document.getElementById("_d").innerHTML = 0 + "天"; document.getElementById("_h").innerHTML = 0 + "时"; document.getElementById("_m").innerHTML = 0 + "分"; document.getElementById("_s").innerHTML = 0 + "秒"; clearInterval(timer); } } setInterval(countTime, 0); //setInterval() 方法可按照指定的周期（以毫秒计）来调用函数或计算表达式。 </script> </head> <body> <div> <span id="_d">00</span> <span id="_h">00</span> <span id="_m">00</span> <span id="_s">00</span> </div> </body> </html>