js显示当前时间

闲着没事在闪存里看到有人需要js显示当前时间，就一时兴起写了个。

输出格式：“2013年12月18日 星期三 上午9:05:00 ”。

<script type="text/javascript">
 function tick() {
            var hours, minutes, seconds, xfile;
            var intHours, intMinutes, intSeconds;
            var today, theday;
            today = new Date();
            var d = [
"星期日",
"星期一",
"星期二",
"星期三",
"星期四",
"星期五",
"星期六"];
            theday = today.getFullYear() + "年" + [today.getMonth() + 1] + "月" + today.getDate() + "日 " + d[today.getDay()];
            intHours = today.getHours();
            intMinutes = today.getMinutes();
            intSeconds = today.getSeconds();
            if (intHours == 0) {
                hours = "12:";
                xfile = " 午夜";
            } else if (intHours < 12) {
                hours = intHours + ":";
                xfile = " 上午";
            } else if (intHours == 12) {
                hours = "12:";
                xfile = " 正午";
            } else {
                intHours = intHours - 12
                hours = intHours + ":";
                xfile = " 下午";
            }
            if (intMinutes < 10) {
                minutes = "0" + intMinutes + ":";
            } else {
                minutes = intMinutes + ":";
            }
            if (intSeconds < 10) {
                seconds = "0" + intSeconds + " ";
            } else {
                seconds = intSeconds + " ";
            }
            timeString = theday + xfile + hours + minutes + seconds;
            document.getElementById("lbClock").innerHTML = timeString;
            window.setTimeout("tick();", 100);
        }
        window.onload = tick;
</script>

PS：感谢undefined的指点，简化了很多。

以上是客户端时间，那么要想显示服务器时间怎么办呢？对于精确度要求不高的情况有个方案：

页面第一次打开时获取一次服务器时间，然后根据这个时间通过js计时器计算并显示时间。

//计算时间
function getTime() {
    serverTime.setSeconds(serverTime.getSeconds() + 1);
    myTime.innerHTML = getTimeStr(serverTime);
}
//输出时间格式  2014-01-01 00:01:01
function getTimeStr(t) {
    var result = t.getFullYear() + "-" + bl(t.getMonth() + 1) + "-" + bl(t.getDate()) + " " + bl(t.getHours()) + ":" + bl(t.getMinutes()) + ":" + bl(t.getSeconds());
    return result;
}
//补零
function bl(n) {
    return n.toString().length > 1 ? n : "0" + n;
}
//显示时间
function showTime() {
    myTime = document.getElementById("lbClock");
    //new Date无法转换 2014-01-01 01:01:01， - 替换成 / 之后转换正常
    serverTime = new Date(myTime.innerHTML.replace(/-/g, "/"));
    setInterval(getTime, 1000);
}
var myTime = '', serverTime = '';
window.onload = showTime;