function DateSelect_SelectedIndexChanged(ControlID)
{
	dyel = document.getElementById(ControlID + "_DAY");
	mnel = document.getElementById(ControlID + "_MONTH");
	yrel = document.getElementById(ControlID + "_YEAR");
	
	maximum = DateSelect_MaxMonth(dyel[dyel.selectedIndex].value, mnel[mnel.selectedIndex].value, yrel[yrel.selectedIndex].value);
	
	if (maximum <  dyel[dyel.selectedIndex].value)
	{
		dyel[maximum-1].selected = true;
	}
}

function DateSelect_MaxMonth(d,m,y)
{
	if (m == 2)
		return (((y % 4 == 0) && (y % 100 != 0)) || (y % 400 == 0)) ? 29 : 28;
	else
		return (m == 4 || m == 6 || m == 9 || m == 11) ? 30 : 31;
}