一个不错的js html页面倒计时可精确到秒，很简单，但和实用
<!doctype html> <html> <head> <meta charset="utf-8"> </head> <body> <DIV id="CountMsg"> <span id="t_d">00天</span> <span id="t_h">00时</span> <span id="t_m">00分</span> <span id="t_s">00秒</span> </DIV> <script type="text/javascript"> function getRTime(){ var EndTime= new Date('2014/10/23 10:00:00'); //截止时间 var NowTime = new Date(); var t =EndTime.getTime() - NowTime.getTime(); /*var d=Math.floor(t/1000/60/60/24); t-=d*(1000*60*60*24); var h=Math.floor(t/1000/60/60); t-=h*60*60*1000; var m=Math.floor(t/1000/60); t-=m*60*1000; var s=Math.floor(t/1000);*/ var d=Math.floor(t/1000/60/60/24); var h=Math.floor(t/1000/60/60%24); var m=Math.floor(t/1000/60%60); var s=Math.floor(t/1000%60); document.getElementById("t_d").innerHTML = d + "天"; document.getElementById("t_h").innerHTML = h + "时"; document.getElementById("t_m").innerHTML = m + "分"; document.getElementById("t_s").innerHTML = s + "秒"; } setInterval(getRTime,1000); </script> </body> </html>