Try this:
function worldClock(zone, region){
var dst = 0
var time = new Date()
var gmtMS = time.getTime() + (time.getTimezoneOffset() * 60000)
var gmtTime = new Date(gmtMS)
var day = gmtTime.getDate()
var month = gmtTime.getMonth()
var year = gmtTime.getYear()
if(year < 1000){
year += 1900
}
var monthArray = new Array("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December")
var monthDays = new Array("31", "28", "31", "30", "31", "30", "31", "31", "30", "31", "30", "31")
if (year%4 == 0){
monthDays = new Array("31", "29", "31", "30", "31", "30", "31", "31", "30", "31", "30", "31")
}
if(year%100 == 0 && year%400 != 0){
monthDays = new Array("31", "28", "31", "30", "31", "30", "31", "31", "30", "31", "30", "31")
}
var hr = gmtTime.getHours() + zone
var min = gmtTime.getMinutes()
var sec = gmtTime.getSeconds()
if (hr >= 24){
hr = hr-24
day -= -1
}
if (hr < 0){
hr -= -24
day -= 1
}
if (hr < 10){
hr = " " + hr
}
if (min < 10){
min = "0" + min
}
if (sec < 10){
sec = "0" + sec
}
if (day <= 0){
if (month == 0){
month = 11
year -= 1
}
else{
month -= 1
}
day = monthDays[month]
}
if(day > monthDays[month]){
day = 1
if(month == 11){
month = 0
year -= -1
}
else{
month -= -1
}
}
if (region == "Europe"){
var startDST = new Date()
var endDST = new Date()
startDST.setMonth(2)
startDST.setHours(1)
startDST.setDate(31)
var dayDST = startDST.getDay()
startDST.setDate(31-dayDST)
endDST.setMonth(9)
endDST.setHours(0)
endDST.setDate(31)
dayDST = endDST.getDay()
endDST.setDate(31-dayDST)
var currentTime = new Date()
currentTime.setMonth(month)
currentTime.setYear(year)
currentTime.setDate(day)
currentTime.setHours(hr)
if(currentTime >= startDST && currentTime < endDST){
dst = 1
}
}
if (dst == 1){
hr -= -1
if (hr >= 24){
hr = hr-24
day -= -1
}
if (hr < 10){
hr = " " + hr
}
if(day > monthDays[month]){
day = 1
if(month == 11){
month = 0
year -= -1
}
else{
month -= -1
}
}
return monthArray[month] + " " + day + ", " + year + " " + hr + ":" + min + ":" + sec + " DST"
}
else{
return monthArray[month] + " " + day + ", " + year + " " + hr + ":" + min + ":" + sec
}
}
var amstime = worldClock(1, "Europe") ;
alert("amsterdam time is: " + amstime);
LIVE DEMO
SOURCE Take a look at this source code to understand how to update the time every second.