js 倒计时

<!--单位：秒-->
剩余时间：<span id="endtime">900000</span>
<script type="text/javascript">
    var CID = "endtime";
    if (window.CID != null) {
        var iTime = document.getElementById(CID).innerText;
        var Account;
        RemainTime();
    }
    function RemainTime() {
        var iDay, iHour, iMinute, iSecond;
        var sDay = "", sHour = "", sMinute = "", sSecond = "", sTime = "";
        if (iTime >= 0) {
            iDay = parseInt(iTime / 24 / 3600);
            if (iDay > 0) {
                sDay = iDay + "天";
            }
            iHour = parseInt((iTime / 3600) % 24);
            if (iHour > 0) {
                sHour = iHour + "小时";
            }
            iMinute = parseInt((iTime / 60) % 60);
            if (iMinute > 0) {
                sMinute = iMinute + "分钟";
            }
            iSecond = parseInt(iTime % 60);
            if (iSecond >= 0) {
                sSecond = iSecond + "秒";
            }
            if ((sDay == "") && (sHour == "")) {
                sTime = "<span style='color:darkorange'>" + sMinute + sSecond + "</font>";
            }
            else {
                sTime = sDay + sHour + sMinute + sSecond;
            }
            if (iTime == 0) {
                clearTimeout(Account);
                sTime = "<span style='color:green'>时间到了！</span>";
            }
            else {
                Account = setTimeout("RemainTime()", 1000);
            }
            iTime = iTime - 1;
        }
        else {
            sTime = "<span style='color:red'>倒计时结束！</span>";
        }
        document.getElementById(CID).innerHTML = sTime;
    }
</script>