function checkForm(which, step, check, action) {
	if (step==0) {
		var requiredFields	= new Array ("vorname", "name", "email", "gebdat", "kennung", "passwort", "passwort1", "adresse", "plz", "ort", "land");
		if (which.zahlungsart.value=="one")
			requiredFields.push("telefon");

		if(which.type.value=="new")	{
			if (which.zahlungsart.value=="cbcard") {
				requiredFields.push("agb", "agb_cbcard", "konto_nr", "blz", "partnerkarten");
			}
			if (which.zahlungsart.value=="maestro")
				requiredFields.push("agb", "agb_maestro");
			if (which.zahlungsart.value=="one")
				requiredFields.push("agb", "agb_one");
			if (which.zahlungsart.value=="kk") {
				requiredFields.push("agb", "agb_kk", "karten_nr", "gueltig_bis");
				which.gueltig_bis.value = '01.' + which.gueltig_bis_monat.value + '.' + which.gueltig_bis_jahr.value;
			}
			requiredFields.push("agb_rueckgabe");
		}
	}
	else
		var requiredFields	= new Array();

	var m_feldnamen= new Array();
	m_feldnamen["vorname"]		= "Vorname";
	m_feldnamen["name"]			= "Nachname";
	m_feldnamen["email"]		= "E-Mail";
	m_feldnamen["gebdat"]		= "Geburtsdatum";
	m_feldnamen["kennung"]		= "Username";
	m_feldnamen["passwort"]		= "Passwort";
	m_feldnamen["passwort1"]	= "Passwort";
	m_feldnamen["adresse"]		= "Straße";
	m_feldnamen["plz"]			= "PLZ";
	m_feldnamen["ort"]			= "Ort";
	m_feldnamen["land"]			= "Land";
	m_feldnamen["telefon"]		= "Telefon";

	var error = 0;
	var field_select = 0;
	var field_select2 = null;				
	var j = 0;
	var address_contains_streetno = false;
	var s;
	var m_b;
	var tempObject;

	var checkFilters = new Array();
	checkFilters["email"] = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	checkFilters["kennung"] = /^([^ \t\r\n\v\f;]{3,})+$/;
	checkFilters["passwort"] = /^([^ \t\f;]{3,})+$/;
	checkFilters["partnerkarten"] = /^[0-9]+$/;

	var checkExclude = new Array();
	checkExclude ["gebdat"] = "exclude";
	checkExclude ["email"] = "exclude";
	checkExclude ["gueltig_bis"] = "exclude";
	
	which.gebdat.value = which.gebtag.value + '.' + which.gebmonat.value + '.' + which.gebjahr.value;
	if (which.gebdat.value=="..")
		which.gebdat.value = "";

	pass = which.passwort.value;

	which.step.value = step;
	which.action.value = action;
	
	var type	= which.type.value;

	// A string may only be composed of letters on the terminal keyboard
	// , ist auch nicht erlaubt, da Befehle an den CBW-Server das als Trennzeichen verwenden!
	var m_allowed_letters = "1234567890abcdefghijklmnopqrstuvwxyzüöäß@/.-_ ";
	var m_illegal_letter = false;
	var m_errormsg = '';

	for(i=0; i<requiredFields.length; i++) {
		if ((requiredFields[i]!="agb")&&(requiredFields[i]!="passwort1")) {	// these fields will not be checked
			var tempObject = eval("which."+ requiredFields[i]);
			m_valuestring=tempObject.value.toLowerCase();
			for(j=0; j<m_valuestring.length;  j++) {
				if (m_allowed_letters.indexOf(m_valuestring.charAt(j))==-1) {
					m_illegal_letter=true;
					if (m_errormsg!='')
						m_errormsg+='\n';
					m_errormsg+=m_feldnamen[requiredFields[i]]+' enthält ungültige Zeichen.';
					if (field_select2==null) 
						field_select2 = i;
					break;
				}
			}
		}
	}
	
	if (m_illegal_letter) {
		m_errormsg+='\n'+'Nur alphanumerische Zeichen, Leerzeichen und die Zeichen @/.-_ sind erlaubt!';	
	}
	
	// username and password must be different
	if ((which.kennung.value!='')&&(which.passwort.value!='')) {
		if (which.kennung.value.toLowerCase()==which.passwort.value.toLowerCase()) {
			if (m_errormsg!='')
				m_errormsg+='\n';
			m_errormsg+='Der Benutzername und das Passwort dürfen nicht ident sein!';	
			if (field_select2==null) 
				field_select2=4;
		}
	}

	// bei zahlungsart sms-one telefonnr. prüfen
	if ((which.zahlungsart.value=="one")&&(which.telefon.value!="")) {
		s = which.telefon.value;
		if (s.length<10) {
			if (m_errormsg!='')
				m_errormsg+='\n';
			m_errormsg+='Die Telefonnummer ist zu kurz.';
			if (field_select2==null) 
				field_select2=11;
		}
	}
	
	if ((which.zahlungsart.value=="cbcard")&&(which.blz.value!="")) {
		m_b = true;
		for (j=0; j<which.blz.value.length; j++) {
			if ((which.blz.value.charCodeAt(j)<48)||(which.blz.value.charCodeAt(j)>57)) {
				m_b = false;
				break;
			}
		}			
		if (!m_b) {
			if (m_errormsg!='')
				m_errormsg+='\n';
			m_errormsg+='Die BLZ ist nicht korrekt, es sind nur Ziffern erlaubt (z.B. 60000).';	
			if (field_select2==null) 
				field_select2=14;
		}
		
		if (which.blz.value.length!=5) {
			if (m_errormsg!='')
				m_errormsg+='\n';
			m_errormsg+='Die BLZ muss 5-stellig sein.';	
			if (field_select2==null) 
				field_select2=14;
		}
	}
	
	if ((which.zahlungsart.value=="cbcard")&&(which.konto_nr.value!="")) {
		m_b = true;
		for (j=0; j<which.konto_nr.value.length; j++) {
			if ((which.konto_nr.value.charCodeAt(j)<48)||(which.konto_nr.value.charCodeAt(j)>57)) {
				m_b = false;
				break;
			}
		}
						
		if (!m_b) {
			if (m_errormsg!='')
				m_errormsg+='\n';
			m_errormsg+='Die Kontonr. ist nicht korrekt, es sind nur Ziffern erlaubt (z.B. 12345678).';	
			if (field_select2==null) 
				field_select2=13;
		}
		
		if (which.konto_nr.value.length>11) {
			if (m_errormsg!='')
				m_errormsg+='\n';
			m_errormsg+='Die Kontonr. darf maximal 11-stellig sein.';
			if (field_select2=="")
				field_select2=13;
		}
	}	
		
	if (check == "y" && error==0) {	
		for (i=0; i<requiredFields.length; ++i) {
			tempObject = eval("which." + requiredFields[i]);
			imageName = tempObject.name + "_req";
			field = tempObject.name;
			exclude = checkExclude[field];
			
			if (!exclude && (((tempObject.type == "text" || tempObject.type == "password" || tempObject.type == "hidden") && tempObject.value == "") || (tempObject.type == "select-one" && tempObject.selectedIndex == 0))) {
				//document[imageName].src = eval(imageName + ".src");
				document.getElementById(imageName).style.visibility='visible';
				document.getElementById(imageName).innerHTML=eval(imageName);
				error += 1;
				if (error == 1) field_select = i;
			} else {
				control = 0;
				// Wenn E-Mail leer, dann keine Prüfung
				if (field=="email") {
					if ((tempObject.value=="")&&(which.rechnungsversand.value!=2))
						filter="";
					else
						filter = checkFilters[field];
				}
				else
					filter = checkFilters[field];
				if (filter && !filter.test(tempObject.value)) {
					//document[imageName].src = eval(field + "_err" + ".src");
					document.getElementById(imageName).style.visibility='visible';
					document.getElementById(imageName).innerHTML=eval(field + "_err");
					error += 1;
					if (error == 1) field_select = i;
					control += 1;
				}
				
				if (control == 0) {
					if (tempObject.name == "passwort1" && tempObject.value != "" && tempObject.value != pass) {
						//document[imageName].src = eval(field + "_err" + ".src");
						document.getElementById(imageName).style.visibility='visible';
						document.getElementById(imageName).innerHTML=eval(field + "_err");
						error += 1;
						if (error == 1) field_select = i;
					} 
					else if (tempObject.name == "adresse" && tempObject.value != "") {
						// in adresse muss hausnr. enthalten sein
						address_contains_streetno = false;
						for (j=0; j<tempObject.value.length; j++) {
							if ((tempObject.value.charCodeAt(j)>=48) && (tempObject.value.charCodeAt(j)<=57)) {
							//if (!isNaN(tempObject.value.charAt(j))) 
								address_contains_streetno = true;
								break;
							}
						}
						if (!address_contains_streetno) {
							//document[imageName].src = eval(field + "_err" + ".src");
							document.getElementById(imageName).style.visibility='visible';
							document.getElementById(imageName).innerHTML=eval(field + "_err");
							error += 1;
							field_select = i;
						} else {
							//document[imageName].src = eval("no_req" + ".src");
							document.getElementById(imageName).style.visibility='hidden';
							document.getElementById(imageName).innerHTML='';
						}
					}	
					else {
						if (tempObject.name == "gebdat") {
							if ((tempObject.value != "") && (!checkDate(which))) {
								//document[imageName].src = eval(field + "_err" + ".src");
								document.getElementById(imageName).style.visibility='visible';
								document.getElementById(imageName).innerHTML=eval(field + "_err");
								error += 1;
							} else {
								//document[imageName].src = eval("no_req" + ".src");
								document.getElementById(imageName).style.visibility='hidden';
								document.getElementById(imageName).innerHTML='';
							}
						}
						else if (tempObject.name == "gueltig_bis") {
							if ((tempObject.value != "..") && (!lib_IsDate(which.gueltig_bis.value))) {
								//document[imageName].src = eval(field + "_req" + ".src");
								document.getElementById(imageName).style.visibility='visible';
								document.getElementById(imageName).innerHTML=eval(field + "_req");
								error += 1;
							} else {
								//document[imageName].src = eval("no_req" + ".src");
								document.getElementById(imageName).style.visibility='hidden';
								document.getElementById(imageName).innerHTML='';
							}
						}
						else {
							//document[imageName].src = eval("no_req" + ".src");
							document.getElementById(imageName).style.visibility='hidden';
							document.getElementById(imageName).innerHTML='';
						}
					}
				}
			}
		}
	}

	if ((error != 0)||(m_errormsg!="")) {		
		if (field_select2==null)
			field_select2=-1;
		
		if ((field_select2!=-1)&&(field_select2<=field_select))
			field_select=field_select2;

		if (m_errormsg!="")
			alert(m_errormsg);
		
		s = requiredFields[field_select];
		if (s.indexOf('agb')==-1) {	// focus auf checkbox liefert sonst fehler
			eval("which.field_" + requiredFields[field_select] + ".focus()");
		}
	} else {
		SetFields();
		if (type=="change")
			which.step.value = parseInt(which.step.value) + 1;
		which.submit();
	}
}

function checkAGB(agb_checkbox, agb_field) {
	if(agb_checkbox.checked == true) {
		agb_field.value = "x";
	} else {
		agb_field.value = "";
	}
}

function focusUsername(which) {
	which.kennung.focus();
	which.kennung.select();
}

function checkNewsletter(which) {
	if(which.check_news.checked == true) {
		which.newsletter.value = "X";
	} else {
		which.newsletter.value = "";
	}
}

function clearField(field,str) {
	val	= field.value;
	if (val.match(str) == str)
		field.value = '';
}

function showFile(File) {
	window.open(File, "Info", "width=620,height=480,resizeable=yes,scrollbars=yes").focus();
}

function checkDate(which) {
	day		= which.gebtag.value;
	month	= which.gebmonat.value;
	year 	= which.gebjahr.value;
	month = month - 1;  
	var tempDate = new Date(year,month,day);
	if ((year == tempDate.getFullYear()) && (month == tempDate.getMonth()) && (day == tempDate.getDate())) {
		return true;
	} else {
		return false;
	}
}

function lib_IsDate(date) {
	/* check input of date field for format + validity */ 
	filter	= /^(\d{1,2})([\.\-\|\,])(\d{1,2})([\.\-\|\,])(\d{2}|\d{4})$/;
	control	= date.match(filter);	
	
	if (control == null) {
		/* format is not correct */
		return false;
	} else {
		/* format is correct - check validity */ 
		day	= control[1];
		month	= control[3];
		year	= control[5];
		
		if (year.length < 4) {
			conv_date	= new Date();
			year		= conv_date.getFullYear().toString().substring(0,2)+year;
		}

		ctr_date	= new Date(year,month-1,day)
		d		= ctr_date.getDate();
		m		= parseInt(ctr_date.getMonth())+1;
		y		= ctr_date.getFullYear();
		y		= y.toString().substring(y.toString().length-year.length);

		if (d!=day || m!=month || y!=year) {
			/* date is not valid */
			return false;
		} else {	
			/* date is valid */
			return true;
		}
	}
}