Help on adjusting time?

[Talon]

Here's the working live time I got it running on my fluxcp but I'm not sure how to make it 3 minutes slower, perhaps anyone knows it?
 
 

< script type="text/javascript">

function GetClock(){
d = new Date();
dx = d.toGMTString();
dx = dx.substr(0,dx.length -3);
d.setTime(Date.parse(dx))
d.setSeconds(d.getSeconds() + <?php date_default_timezone_set('America/New_York'); echo date('Z'); ?>);
nhour  = d.getHours();
nmin   = d.getMinutes();
nsec   = d.getSeconds();

     if(nhour ==  0) {ap = " AM";nhour = 12;} 
else if(nhour <= 11) {ap = " AM";} 
else if(nhour == 12) {ap = " PM";} 
else if(nhour >= 13) {ap = " PM";nhour -= 12;}

if(nmin <= 9) {nmin = "0" +nmin;}
if(nsec <= 9) {nsec = "0" +nsec;}


document.getElementById('clockbox').innerHTML=""+nhour+":"+nmin+":"+nsec+ap+"";
setTimeout("GetClock()", 1000);
}
window.onload=GetClock;
</script>

Already fixed it, here's the code if anyone wants it 

<script type="text/javascript">
offset = Math.round(new Date().getTime() / 1000);

function GetClock(){
tzOffset = -5;//set this to the number of hours offset from UTC
tzOffset1 = -3;
tzOffset2 = -15;

d = new Date();
dx = d.toGMTString();
dx = dx.substr(0,dx.length -3);
d.setTime(Date.parse(dx))
d.setHours(d.getHours() + tzOffset);
d.setMinutes(d.getMinutes() + tzOffset1);
d.setSeconds(d.getSeconds() + tzOffset2);
nhour  = d.getHours();
nmin   = d.getMinutes();
nsec   = d.getSeconds();

     if(nhour ==  0) {ap = " AM";nhour = 12;} 
else if(nhour <= 11) {ap = " AM";} 
else if(nhour == 12) {ap = " PM";} 
else if(nhour >= 13) {ap = " PM";nhour -= 12;}

if(nmin <= 9) {nmin = "0" +nmin;}
if(nsec <= 9) {nsec = "0" +nsec;}


document.getElementById('clockbox').innerHTML=""+nhour+":"+nmin+":"+nsec+ap+"";
setTimeout("GetClock()", 1000);
}
window.onload=GetClock;
</script>
<div id="clockbox"></div>

Edited October 12, 2014 by Talon

[Emistry]

^{you can just simply adjust your server time, all the website follow the time of your server/vps.}

[Talon]

May I know the scripts of it? So it could shorten my codes for faster loading time?  

Edited October 12, 2014 by Talon