function checkDates() {
		var arrivalYear = document.forms['Formular'].year.value
		var arrivalMonth = document.forms['Formular'].month.value-1
		var arrivalDay = document.forms['Formular'].day.value
		var departureYear = document.forms['Formular'].year1.value
		var departureMonth = document.forms['Formular'].month1.value-1
		var departureDay = document.forms['Formular'].day1.value
		var today = new Date();
		var arrival = new Date(arrivalYear,arrivalMonth, arrivalDay);
		var departure = new Date(departureYear,departureMonth, departureDay);
		
		if (arrival < today) {
			alert("Das Anreisedatum liegt in der Vergangenheit!");
			return false;
		} 
		if (departure <= arrival) {
			alert("Bitte geben Sie mindestens eine Übernachtung ein");
			return false;
		} 
}

changed = false;

function setDates() {
	if (!changed) {
		var daystodeparture = 7
		var arrivalYear = document.forms['Formular'].year.value
		var arrivalMonth = document.forms['Formular'].month.value-1
		var arrivalDay = document.forms['Formular'].day.value
		var arrival = new Date(arrivalYear,arrivalMonth, arrivalDay);
		var addDate = daystodeparture*1000*60*60*24;// x Tage inzwischen
		var departure = arrival.valueOf() + addDate;
		var newDeparture = new Date();
		newDeparture.setTime(departure);
		
		//Überprüfen auf korrektes datum 
		for (i=0; i<document.forms['Formular'].day.options.length; i++) {
			if (document.forms['Formular'].day.options[i].value == arrival.getDate()) {
				document.forms['Formular'].day.options[i].selected = "true";
			}
		}
		for (i=0; i<document.forms['Formular'].month.options.length; i++) {
			if (document.forms['Formular'].month.options[i].value == arrival.getMonth()+1) {
				document.forms['Formular'].month.options[i].selected = "true";
			}
		}

		//Setzen des Abfahrtsdatum
		if (document.forms['Formular'].day1.type == "select-one") {
			for (i=0; i<document.forms['Formular'].day1.options.length; i++) {
				if (document.forms['Formular'].day1.options[i].value == newDeparture.getDate()) {
					document.forms['Formular'].day1.options[i].selected = "true";
				}
			}
		} 
		
		if (document.forms['Formular'].month1.type == "select-one") {
			for (i=0; i<document.forms['Formular'].month1.options.length; i++) {
				if (document.forms['Formular'].month1.options[i].value == newDeparture.getMonth()+1) {
					document.forms['Formular'].month1.options[i].selected = "true";
				}
			}
		} 

		if (document.forms['Formular'].year1.type == "select-one") {
			for (i=0; i<document.forms['Formular'].year1.options.length; i++) {
				if (document.forms['Formular'].year1.options[i].value == newDeparture.getFullYear()) {
					document.forms['Formular'].year1.options[i].selected = "true";
				}
			}
		} 
	}			
	
}