convert timestamp to utc javascript
function utcformat(d){
d= new Date(d);
var tail= 'GMT', D= [d.getUTCFullYear(), d.getUTCMonth()+1, d.getUTCDate()],
T= [d.getUTCHours(), d.getUTCMinutes(), d.getUTCSeconds()];
if(+T[0]> 12){
T[0]-= 12;
tail= ' pm '+tail;
}
else tail= ' am '+tail;
var i= 3;
while(i){
--i;
if(D[i]<10) D[i]= '0'+D[i];
if(T[i]<10) T[i]= '0'+T[i];
}
return D.join('/')+' '+T.join(':')+ tail;
}