function CheckEmail (emailStr)
 {
  var checkTLD=1;
  var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
  var emailPat=/^(.+)@(.+)$/;
  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=emailStr.match(emailPat);

  if (matchArray==null) {
    alert("Email adres is geen geldige adres!");
    return false;
   }
   var user=matchArray[1];
   var domain=matchArray[2];

   for (i=0; i<user.length; i++) {
     if (user.charCodeAt(i)>127) {
     alert("email adres bevat ongeldige karakters!");
     return false;}}

   for (i=0; i<domain.length; i++) {
     if (domain.charCodeAt(i)>127) {
     alert("Email adres domein extensie bestaat niet!");
     return false;}}

   if (user.match(userPat)==null) {
     alert("Email adres is wellicht verkeerd getypt, controleer!");
     return false;}


   var IPArray=domain.match(ipDomainPat);
   if (IPArray!=null) {

  for (var i=1;i<=4;i++) {
  if (IPArray[i]>255) {
   alert("IP addres is ongeldig!");
   return false;}}

 return true;
}

 
 var atomPat=new RegExp("^" + atom + "$");
 var domArr=domain.split(".");
 var len=domArr.length;
 for (i=0;i<len;i++) {
   if (domArr[i].search(atomPat)==-1) {
   alert("Domein van email is onbekend!");
   return false;}
 }


  if (checkTLD && domArr[domArr.length-1].length!=2 && 
  domArr[domArr.length-1].search(knownDomsPat)==-1) {
  alert("Email adres is verkeerd. Extensie (domein) bestaat niet..");
  return false;}

  if (len<2) {
  alert("Email heeft geen hostnaan !");
  return false;}

 return true;

}