Although document.write
by no way is Java but since the question is tagged as Java. You may try like this to display the time in EST
Date date = new Date();
DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
df.setTimeZone(TimeZone.getTimeZone("America/New_York"));
EDIT:-
However if you want to use that in Javascript then try to use Date.prototype.getTimezoneOffset()
The time-zone offset is the difference, in minutes, between UTC and local time. Note that this means that the offset is positive if the local timezone is behind UTC and negative if it is ahead. For example, if your time zone is UTC+10 (Australian Eastern Standard Time), -600 will be returned. Daylight saving time prevents this value from being a constant even for a given locale.