function toggle(name1, name2)
{	
	var element1 = document.getElementById(name1);
	var element2 = document.getElementById(name2);

	var value = element1.value;
	if(value == "")
	{
		var index = element1.selectedIndex;
		value = element1.options[index].text;
	}

	if(value == 0)
	{		
		element2.disabled = false;
	}
	else
	{
		element2.disabled = true;
	}
}

function check()
{
	
	var first_name = document.getElementsByName("first_name")[0];
	var last_name = document.getElementsByName("last_name")[0];	
	var telephone = document.getElementsByName("telephone")[0];
	var mail = document.getElementsByName("mail")[0];
	var room = document.getElementsByName("room")[0];
	var appartment = document.getElementsByName("appartment")[0];
	
	var period_from_day = document.getElementsByName("period_from_day")[0];
	var period_from_month = document.getElementsByName("period_from_month")[0];
	var period_from_year = document.getElementsByName("period_from_year")[0];
	var period_to_day = document.getElementsByName("period_to_day")[0];
	var period_to_month = document.getElementsByName("period_to_month")[0];
	var period_to_year = document.getElementsByName("period_to_year")[0];

	if(first_name.value == "")
	{
		alert("Bitte geben Sie Ihren Vornamen ein!");
		return false;
	}
	if(last_name.value == "")
	{
		alert("Bitte geben Sie Ihren Namen ein!");
		return false;
	}
	if(telephone.value == "")
	{
		alert("Bitte geben Sie Ihre Telefonnummer ein!");
		return false;
	}
	if(mail.value == "")
	{
		alert("Bitte geben Sie Ihre E-Mail-Adresse ein!");
		return false;
	}

	if(room.options[room.selectedIndex].value == "0" && appartment.options[appartment.selectedIndex].value == "0")
	{
		alert("Bitte wählen Sie entweder ein Zimmer oder eine Ferienwohnung aus!");
		return false;
	}	

	var from_year = parseInt(period_from_year.options[period_from_year.selectedIndex].text);
	var from_month = parseInt(period_from_month.options[period_from_month.selectedIndex].text);
	var from_day = parseInt(period_from_day.options[period_from_day.selectedIndex].text);
	
	var to_year = parseInt(period_to_year.options[period_to_year.selectedIndex].text);
	var to_month = parseInt(period_to_month.options[period_to_month.selectedIndex].text);
	var to_day = parseInt(period_to_day.options[period_to_day.selectedIndex].text);
	
	/*var from = period_from_year.options[period_from_year.selectedIndex].text+"-"+period_from_month.options[period_from_month.selectedIndex].text+"-"+period_from_day.options[period_from_day.selectedIndex].text+" "+"00:00:00";
	var to = period_to_year.options[period_to_year.selectedIndex].text+"-"+period_to_month.options[period_to_month.selectedIndex].text+"-"+period_to_day.options[period_to_day.selectedIndex].text+" "+"00:00:00";
	*/

	/*if(from_year > to_year || (from_year <= to_year && from_month > to_month) || (from_year <= to_year && from_month == to_month && from_day > to_day))
	{
		alert("Bitte überprüfen Sie den Zeitraum. Das Endedatum liegt vor dem Startdatum!");
		return false;
	}*/
	return true;
}