JS实现倒计时

//将字符串格式化为时间
function parseDate(str) {
    var bb = document.getElementById("bb");
    if (typeof str == 'string') {
        var results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) *$/);
        if (results && results.length > 3)
            return new Date(parseInt(results[1], 10), parseInt(results[2], 10) - 1, parseInt(results[3], 10));
        results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2}) *$/);
        if (results && results.length > 6)
            return new Date(parseInt(results[1], 10), (parseInt(results[2], 10) - 1), parseInt(results[3], 10), parseInt(results[4], 10), parseInt(results[5], 10), parseInt(results[6], 10));
        results = str.match(/^ *(\d{4})-(\d{1,2})-(\d{1,2}) +(\d{1,2}):(\d{1,2}):(\d{1,2})\.(\d{1,9}) *$/);
        if (results && results.length > 7)
            return new Date(parseInt(results[1], 10), parseInt(results[2], 10) - 1, parseInt(results[3], 10), parseInt(results[4], 10), parseInt(results[5], 10), parseInt(results[6], 10), parseInt(results[7], 10));
    }
    return null;
}

//倒计时 deadline：截止日期，要求格式为：yyyy-MM-dd 或者 yyyy-MM-dd HH:mm:ss或者 yyyy-MM-dd HH:mm:ss.ms
//       divname：倒计时要显示的位置
//       type：1：显示精确到分；0：显示精确到秒
//       msg1、msg2：当倒计时分别不为0、为0时显示的提示信息
function ShowCountDown(deadline, divname, type, msg1, msg2) {
    var cc = document.getElementById(divname);
    var now = new Date();
    var endDate = parseDate(deadline);
    if (endDate != null) {
        var leftTime = endDate.getTime() - now.getTime();
        if (leftTime > 0) {
            var leftsecond = parseInt(leftTime / 1000);
            var day = Math.floor(leftsecond / (60 * 60 * 24));
            var hour = Math.floor((leftsecond - day * 24 * 60 * 60) / 3600);
            var minute = Math.floor((leftsecond - day * 24 * 60 * 60 - hour * 3600) / 60);
            var second = Math.floor(leftsecond - day * 24 * 60 * 60 - hour * 3600 - minute * 60);
           
            if (cc != null) {
               if (type == 1) {cc.innerHTML = msg1 + day + "天" + hour + "小时" + minute + "分";}
               else { cc.innerHTML = msg1 + day + "天" + hour + "小时" + minute + "分" + second + "秒"; }
            }           
        }
        else {
            cc.innerHTML = msg2;
        } 
    }
}



使用例子：

var interval = 1000;
 window.setInterval(function() { ShowCountDown('2010-6-11 15:36:00', 'div1', 1,'距停止报名还有 ', '活动已结束'); }, interval);