window.onerror = Fehlerbehandlung;

function Fehlerbehandlung (Nachricht, Datei, Zeile) {
  Fehler = "Fehlermeldung:\n" + Nachricht + "\n" + Datei + "\n" + Zeile;
  zeigeFehler();
  return true;
}

function zeigeFehler () {
  alert(Fehler);
}

function Fenster (URL, NAME, BREITE, HOEHE, SCROLL)
{
	var newwin = window.open(URL, NAME, "width="+BREITE+", height="+HOEHE+", scrollbars="+SCROLL);
}

function Schliessen (){
	window.close()
}
function Bildertausch (a)
{
	var bild = new Image ();
	a++;
	if (a>5)
		{
			a=1;
			window.document.images[4].src= "images/titel"+a+".jpg";
			window.setTimeout ('Bildertausch ('+a+')', 4000);			
		}
	else
		{
			window.document.images[4].src= "images/titel"+a+".jpg";
			window.setTimeout ('Bildertausch ('+a+')', 4000);			
		}	
}

function NodesCheck(HTMLid){
	HTMLobject = document.getElementById(HTMLid);
	checkChild = HTMLobject.firstChild
	if (checkChild){
		NodesLoeschen(HTMLobject, checkChild);
	}
}

function NodesSchreiben (HTMLobject, NODEobject){
	HTMLobject.appendChild(NODEobject);
}

function NodesLoeschen (HTMLobject, NODEchild){
	HTMLobject.removeChild(NODEchild);
}

function CheckMandatory(){
	var checks = true;
	var objHtml;
	var objError;
	var expressionMail = /^[a-zA-Z0-9][\w\.-]*@(?:[a-zA-Z0-9][a-zA-Z0-9_-]+\.)+[A-Z,a-z]{2,5}$/;
	var expressionPhone = /^[\d\(\)\/]{3,8}.?[\d\(\)\/]{4,15}$/;
	for (var i=1; i<=3; i++) {
		if (document.VK.elements[i].value == "") {
			switch (i) {
				case 1:
					NodesCheck('error_name');
					objHtml = document.getElementById('error_name')
					objError = document.createTextNode('Es muss ein Name eingegeben werden.');
					objHtml.style.display = "block";
					NodesSchreiben(objHtml, objError);
					checks=false;
					break;
				case 2:
					NodesCheck('error_phone');
					objHtml = document.getElementById('error_phone')
					objError = document.createTextNode('Es muss eine Telefonnummer eingegeben werden.');
					objHtml.style.display = "block";
					NodesSchreiben(objHtml, objError);
					checks=false;
					break;
				case 3:
					NodesCheck('error_mail');
					objHtml = document.getElementById('error_mail')
					objError = document.createTextNode('Es muss eine E-Mail-Adresse eingegeben werden.');
					objHtml.style.display = "block";
					NodesSchreiben(objHtml, objError);
					checks=false;
					break;
			}
		}
		else {
			if ((i==2) && (expressionPhone.test(document.VK.elements[2].value) == false)) {
					NodesCheck('error_phone');
					objHtml = document.getElementById('error_phone')
					objError = document.createTextNode('Eine Telefonnumer muss im Format [VORWAHL] [NUMMER] angegeben werden.');
					NodesSchreiben(objHtml, objError);
					checks=false;
			}
				else if ((i==3) && (expressionMail.test(document.VK.elements[3].value) == false)) {
						NodesCheck('error_mail');
						objHtml = document.getElementById('error_mail')
						objError = document.createTextNode('Das ist keine Gültige E-Mail Adresse!');
						NodesSchreiben(objHtml, objError);
						checks=false;
				}
				else
					switch (i) {
						case 1:
							objHtml = document.getElementById('error_name')
							NodesCheck('error_name');
							objHtml.style.display = "none";
							break;
						case 2:
							objHtml = document.getElementById('error_phone')
							NodesCheck('error_phone');
							objHtml.style.display = "none";
							break;
						case 3:
							objHtml = document.getElementById('error_mail')
							NodesCheck('error_mail');
							objHtml.style.display = "none";
							break;
					}
		}
	}
	if (checks==true) return true;
	else return false;
}