function MailVal(theForm)
{

  // Tjek om der er indtastet en email adresse
  if (theForm.email.value == "")
  {
    alert("Du skal indtaste din email.");
    theForm.email.focus();
    return (false);
  }
  


  var emailPat=/^(.+)@(.+)$/
  var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
  var validChars="\[^\\s" + specialChars + "\]"
  var quotedUser="(\"[^\"]*\")"
  var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
  var atom=validChars + '+'
  var word="(" + atom + "|" + quotedUser + ")"
  var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
  var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")

  var matchArray=theForm.email.value.match(emailPat)
  if (matchArray==null) {
  	alert("Email adressen er ukorrekt (tjek @ og .'er)")
	theForm.email.focus();
	return false
  }
  var user=matchArray[1]
  var domain=matchArray[2]

  // See if "user" is valid 
  if (user.match(userPat)==null) {
    // user is not valid
    alert("Brugernavnet er ukorrekt.")
	theForm.email.focus();
    return false
  }

  /* if the e-mail address is at an IP address (as opposed to a symbolic
   host name) make sure the IP address is valid. */
  var IPArray=domain.match(ipDomainPat)
  if (IPArray!=null) {
    // this is an IP address
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	        alert("Destinations IP addresse er ugyldig!")
			theForm.email.focus();
		return false
	    }
    }
    return true
  }

  // Domain is symbolic name
  var domainArray=domain.match(domainPat)
  if (domainArray==null) {
	alert("Domæne navnet er ugyldigt.")
	theForm.email.focus();
    return false
  }

  /* domain name seems valid, but now make sure that it ends in a
   three-letter word (like com, edu, gov) or a two-letter word,
   representing country (uk, nl), and that there's a hostname preceding 
   the domain or country. */

  /* Now we need to break up the domain to get a count of how many atoms
   it consists of. */
  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>3 || 
    domArr[domArr.length-1].length>4) {
   // the address must end in a two letter or three letter word.
   alert("Adressen skal ende på et 3 eller 4 cifret domæne, eller et 2 cifret land.")
   theForm.email.focus();
   return false
  }

  // Make sure there's a host name preceding the domain.
  if (len<2) {
   var errStr="Email adressen mangler et host navn!"
   alert(errStr)
   theForm.email.focus();
   return false
  }

  // If we've gotten this far, everything's valid!

  return (true);
}