The setUTCHours() method sets the hour in the Date object to the argument hours, an integer from 0 (12:00 a.m. midnight) to 23 (11:00 p.m.) universal time.
The method returns an integer representing the number of milliseconds between midnight January 1, 1970 (GMT) to the new date.
<html>
<script language="JavaScript">
<!--
theDate = new Date();
document.write("Initial milliseconds=",theDate.getTime());
document.write("<br>setUTCHours returned ");
document.write(theDate.setUTCHours(5)," milliseconds.")
document.write("<br>Final milliseconds=",theDate.getTime());