var wrong_date = 0;
var Day0 = 3;
var Year0 = 1999;
var nbrDaysMonth = new Array (31,28,31,30,31,30,31,31,30,31,30,31);

function getFullYear(d)
// Date.getYear() does not work the same way on all browsers !!
{	
	var y = d.getYear();
	if (y < 1000) y+=1900;
	return y;
}

function leap_year(y)
{
	var f = ((y % 4 == 0) && (y % 4000 != 0) && ((y % 100 != 0) || (y % 400 == 0)));
	if (f)
		nbrDaysMonth[1] = 29;
	else
		nbrDaysMonth[1] = 28;
	return f;
}

function getWeekDay(y, m, d)
// must calculate myself because Date.getDay() is buggy in Navigator 4.51 !
{
	var i, ly;
	var nbrDays = Day0;
	var DayOfWeek;			
	if (Year0 < y)
	{
		for (i=Year0;i<y;i++)
		{
			ly = leap_year(i);
			if (ly) 
				nbrDays += 366;
			else
				nbrDays += 365;
		}
	}
	ly = leap_year(y);
	if (m > 0)
	{
		for (i=0;i<m;i++)
			nbrDays += nbrDaysMonth[i];
	}
	nbrDays += d;
	DayOfWeek = nbrDays % 7;	
	return DayOfWeek;
}

function InitDate (my)
{
	var y, h;
	var today = new Date ();	
	y = getFullYear(today);
	my.AnJahr.options[0].text = y.toString(10);
	my.AnJahr.options[1].text = (y+1).toString(10);
	my.AnJahr.options[2].text = (y+2).toString(10);
	my.TheYear.value = (y).toString(10);
	my.AnMonat.selectedIndex = today.getMonth();				
	my.AnTag.selectedIndex = today.getDate() - 1;		
	h = today.getHours() + 2;
	if (h < 11 || h > 23) 
		h = 11;
	my.AnStunden.selectedIndex = h - 10;			
	my.AnMinuten.selectedIndex = 0;
	UpdateDay (my);
}

function UpdateDay (my)
{
	var nWeekDay, i, d, m, y, ly;
	d = my.AnTag.selectedIndex+1;
	m = my.AnMonat.selectedIndex;
	y = my.AnJahr.options[my.AnJahr.selectedIndex].text;
	ly = leap_year(y);	
	if ((m == 0) || (m == 2) || (m == 4) || (m == 6) || (m == 7) || (m == 9) || (m == 11))
	{
		my.AnTag.options[28].text = "29.";
		my.AnTag.options[29].text = "30.";
		my.AnTag.options[30].text = "31.";
	}
	if ((m == 3) || (m == 5) || (m == 8) || (m == 10))
	{
		my.AnTag.options[28].text = "29.";
		my.AnTag.options[29].text = "30.";
		my.AnTag.options[30].text = "";
	}
	if (m == 1)
	{			
		if (ly)																	   
			my.AnTag.options[28].text = "29.";
		else
			my.AnTag.options[28].text = "";
		my.AnTag.options[29].text = "";
		my.AnTag.options[30].text = "";
	}
	if (d > nbrDaysMonth[m])
		wrong_date = 1;
	else
		wrong_date = 0;
	
	if (wrong_date == 1)
	{
		alert ("Falsches Datum, bitte korrigieren.");
	}
	else
	{
		nWeekDay = getWeekDay(y, m, d);
		
	}	
}

function Form_Check()
{
	if (wrong_date == 1)
	{
		alert ("Falsches Datum, bitte korrigieren.");
		return false;
	}
	else
		return true;
}