function checkdata(theForm)
{
    if (!emailCheck(theForm.emailguest.value))
        { theForm.emailguest.focus();	return (false); }
   	return (true)
}
function emailCheck (emailStr)
{
    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]

    if (user.match(userPat)==null)
        {
            alert("The email 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("Email Destination IP address is invalid!");

                      return false;
                     }
                }
            //return true;
        }

    var domainArray=domain.match(domainPat)
    if (domainArray==null)
        {
         alert("The email domain name doesn't seem to be valid.");
            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>3)
        {
            alert("The email address must end in a three-letter domain, or two letter country.");
            return false;
        }

    if (len<2)
        {
            var errStr="This email address is missing a hostname!";
            alert(errStr);
            return false;
        }

    return true;
}