Strange day calander [js]

i noticed a strange problem

dDate = new date(2004, 10, 31);
alert(dDate.getUTCDay());

now if your computer is set at India time (+5:30), it gives 2
and if it is set at GMT, it gives 3

so its tuesday on 31st in UK and wednsday on 31st in India ?

help me out please !!!