function emailCheck (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 +")*$");
   var matchArray=emailStr.match(emailPat);
   if (matchArray==null) {
      //alert("Email address seems incorrect (check @ and .'s)");
      return false;
   }
   var user=matchArray[1];
   var domain=matchArray[2];
   for (i=0; i<user.length; i++) {
      if (user.charCodeAt(i)>127) {
         //alert("Ths username contains invalid characters.");
         return false;
      }
   }
   for (i=0; i<domain.length; i++) {
      if (domain.charCodeAt(i)>127) {
         //alert("Ths domain name contains invalid characters.");
         return false;
      }
   }
   if (user.match(userPat)==null) {
      //alert("The username doesn't seem to be valid.");
      return false;
   }
   var IPArray=domain.match(ipDomainPat);
   if (IPArray!=null) {
      for (var i=1;i<=4;i++) {
         if (IPArray[i]>255) {
            //alert("Destination IP address is invalid!");
            return false;
         }
      }
      return true;
   }
   var atomPat=new RegExp("^" + atom + "$");
   var domArr=domain.split(".");
   var len=domArr.length;
   for (i=0;i<len;i++) {
      if (domArr[i].search(atomPat)==-1) {
         //alert("The domain name does not seem to be valid.");
         return false;
      }
   }
   if (checkTLD && domArr[domArr.length-1].length!=2 && 
    domArr[domArr.length-1].search(knownDomsPat)==-1) {
      //alert("The address must end in a well-known domain or two letter " + "country.");
      return false;
   }
   if (len<2) {
      //alert("This address is missing a hostname!");
      return false;
   }
   return true;
}

function checkRegistration() {
   var f = document.forms.frmRegister;
   var msg = '';
   if (f.txtUserName.value == '') {
      msg = msg + " - Username is required\n";
   }
   if (f.txtPass.value == '') {
      msg = msg + " - Password is required\n";
   }
   if (f.txtEmail.value == '') {
      msg = msg + " - Email address is required\n";
   } else if (!emailCheck(f.txtEmail.value)) {
      msg = msg + " - Invalid Email Address\n";
   }
   if (f.txtAge.value == '') {
      msg = msg + " - Age is required\n";
   }

   if (msg != '') {
      alert("Please fill in form fields before submitting:\n" + msg);
      return false;
   }
   return true;
}