function emailCheck (emailStr)

 {
  var emailPat=/^(.+)@(.+)$/
  var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
  var validChars="\[^\\s" + specialChars + "\]"
  var quotedUser="(\"[^\"]*\")"
  var atom=validChars + '+'
  var word="(" + atom + "|" + quotedUser + ")"
  var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
  var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
  var matchArray=emailStr.match(emailPat)




   if(document.Formular.vorname.value == "")
    {
     alert("Please enter your first name!");
     document.Formular.vorname.focus();
     return false;
    }
   if(document.Formular.nachname.value == "")
    {
     alert("Please enter your last name!");
     document.Formular.nachname.focus();
     return false;
    }
    if(document.Formular.telefon.value == "")
    {
     alert("Please enter your phone number!");
     document.Formular.telefon.focus();
     return false;
    }
   if((document.Formular.gebdat.value == "") || (document.Formular.gebdat.value == "DD.MM.YYYY"))
    {
     alert("Please enter your birth date!");
     document.Formular.gebdat.focus();
     return false;
    }
   if((document.Formular.kursbeginn.value == "") || (document.Formular.kursbeginn.value == "DD.MM.YYYY"))
    {
     alert("Please enter the day you wish to start your course!");
     document.Formular.kursbeginn.focus();
     return false;
    }

	var idSelected = false;
	for (var i=0; i<document.Formular.id.length; i++)
		if (document.Formular.id[i].checked)
			idSelected = true;
	if (idSelected == false)
	{
		alert("Please select an item!");
        return false;
	}


  if (matchArray==null) {
  alert("Please enter your correct email address!")
  document.Formular.email.focus();
  return false
  }
  var user=matchArray[1]
  var domain=matchArray[2]

  if (user.match(userPat)==null) {
    alert("Please check the username of the email address! (john@, office@)")
    document.Formular.email.focus();
    return false
  }

   var domainArray=domain.match(domainPat)
   if (domainArray==null) {
	alert("Please check your domain! (@microsoft.)")
    document.Formular.email.focus();
    return false
   }
   var atomPat=new RegExp(atom,"g")
   var domArr=domain.match(atomPat)
   var len=domArr.length
   if (domArr[domArr.length-1].length<2 ||
    domArr[domArr.length-1].length>4) {
   alert("Please check your address! (.net, .com)")
    document.Formular.email.focus();
   return false
   }
   if (len<2) {
   var errStr="Please check your address! (.net, .com)"
   alert(errStr)
    document.Formular.email.focus();
   return false
   }

   return true;
   }