javascript 显示当前系统时间代码

<script language=JavaScript>
var timerID = null;
var timerRunning = false;
function stopclock (){
if(timerRunning)
clearTimeout(timerID);
timerRunning = false;}
function startclock () {
stopclock();
showtime();}
function showtime () {
var now = new Date();
var hours = now.getHours();
var minutes = now.getMinutes();
var seconds = now.getSeconds()
var timeValue = "" +((hours >= 12) ? "下午 " : "上午 " )
timeValue += ((hours >12) ? hours -12 :hours)
timeValue += ((minutes < 10) ? ":0" : ":") + minutes
timeValue += ((seconds < 10) ? ":0" : ":") + seconds
document.clock.thetime.value = timeValue;
timerID = setTimeout("showtime()",1000);
timerRunning = true;}
</SCRIPT>