function chkFormular()
  {
   
   if(document.Formular.Anreisetag.value == "")
    {
     alert("Please tell us the day of your arrival!");
     document.Formular.Anreisetag.focus();
     return false;
    }
   
   if(document.Formular.Abreisetag.value == "")
    {
     alert("Please tell us the day of your leaving!");
     document.Formular.Abreisetag.focus();
     return false;
    }
   
    if(document.Formular.Einzelzimmer.value == ""
	&& document.Formular.Doppelzimmer.value ==""
	&& document.Formular.Dreibettzimmer.value == ""
	&& document.Formular.Vierbettzimmer.value == ""
	)
    {
     alert("Please choose the number of rooms !");
     document.Formular.Einzelzimmer.focus();
     return false;
    }
   
   var chkZ = 1;
   for(i=0;i<document.Formular.Einzelzimmer.value.length;++i)
     if(document.Formular.Einzelzimmer.value.charAt(i) < "0"
     || document.Formular.Einzelzimmer.value.charAt(i) > "9")
       chkZ = -1;
   if(chkZ == -1)
   {
     alert("number of single rooms contains character(s) !");
     document.Formular.Einzelzimmer.focus();
     return false;
    }
  
	var chkZ = 1;
   for(i=0;i<document.Formular.Doppelzimmer.value.length;++i)
     if(document.Formular.Doppelzimmer.value.charAt(i) < "0"
     || document.Formular.Doppelzimmer.value.charAt(i) > "9")
       chkZ = -1;
   if(chkZ == -1)
   {
     alert("Number of double rooms contains character(s) !");
     document.Formular.Doppelzimmer.focus();
     return false;
    }
      
   if(document.Formular.Familienname.value == "")
    {
     alert("Tell us your name please!");
     document.Formular.Familienname.focus();
     return false;
    }
   
       
   if(document.Formular.Ort.value == "")
    {
     alert("Tell us the name of your city!");
     document.Formular.Ort.focus();
     return false;
    }
   if(document.Formular.Email.value == "")
    {
     alert("We need an e-mail-address!");
     document.Formular.Email.focus();
     return false;
    }
   
   if(document.Formular.Email.value.indexOf('@') == -1)
    {
     alert("Sorry, but this is not a valid e-mail-address!");
     document.Formular.Email.focus();
     return false;
    }
   
   
  }