实际项目中，需求一个倒计时秒杀功能，每天下午6点后，计算距离第二天上午10点的小时、分钟、秒数，计时到第二天上午10点后开启抢购功能；代码如下：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> <script src="https://www.jb51.net/js/jquery-1.11.1.min.js"></script> </head> <body οnlοad="leftTimer();"> <p> <span>00</span> <span>00</span> <span>00</span> </p> <p></p> <script> function leftTimer(year,month,day,hour,minute,second){ var newDate = new Date(); var newDate1 = new Date(year,month-1,day,hour,minute,second); var leftTime = (new Date(year,month-1,day,hour,minute,second)) - (new Date()); //计算剩余的毫秒数 var days = parseInt(leftTime / 1000 / 60 / 60 / 24 , 10); //计算剩余的天数 var hours = parseInt(leftTime / 1000 / 60 / 60 % 24 , 10); //计算剩余的小时 var minutes = parseInt(leftTime / 1000 / 60 % 60, 10);//计算剩余的分钟 var seconds = parseInt(leftTime / 1000 % 60, 10);//计算剩余的秒数 if (seconds<0) { $(".tit_right").css('display', 'none'); $("#juli").text("开始抢购"); } else{ days = fix(days,2); hours = fix(hours,2); minutes = fix(minutes,2); seconds = fix(seconds,2); setTimeout("leftTimer(2017,2,21,11,0,0)",1000); document.getElementById("h").innerHTML=hours; document.getElementB yId("m").innerHTML=minutes; document.getElementById("s").innerHTML=seconds; } } //fix函数：将1~9的1位数转换成01~09的格式 function fix(num, length) { return ('' + num).length < length ? ((new Array(length + 1)).join('0') + num).slice(-length) : '' + num; } </script> </body> </html>