otomatik değişen tarih için yardım

<script>
var dayarray=new Array("Sunday","Monday","Tuesday","Wednesday","Thu rsday","Friday","Saturday")
var montharray=new Array("January","February","March","April","May"," June","July","August","September","October","Novem ber","December")
function getthedate(){
var mydate=new Date()
var year=mydate.getYear()
if (year < 1000)
year+=1900
var day=mydate.getDay()
var month=mydate.getMonth()
var daym=mydate.getDate()
if (daym<10)
daym="0"+daym
var hours=mydate.getHours()
var minutes=mydate.getMinutes()
var seconds=mydate.getSeconds()
var dn="AM"
if (hours>=12)
dn="PM"
if (hours>12){
hours=hours-12
}
if (hours==0)
hours=12
if (minutes<=9)
minutes="0"+minutes
if (seconds<=9)
seconds="0"+seconds
//change font size here
var cdate="<small><font color='000000' face='Arial'><b>"+dayarray[day]+", "+montharray[month]+" "+daym+", "+year+" "+hours+":"+minutes+":"+seconds+" "+dn
+"</b></font></small>"
if (document.all)
document.all.clock.innerHTML=cdate
else if (document.getElementById)
document.getElementById("clock").innerHTML=cdate
else
document.write(cdate)
}
if (!document.all&&!document.getElementById)
getthedate()
function goforit(){
if (document.all||document.getElementById)
setInterval("getthedate()",1000)
}
</script>
<span id="clock"></span>