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 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 domainArray=domain.match(domainPat);

    if (domainArray==null) {
        alert("The 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] != "info") &&
        (domArr[domArr.length-1] != "name") &&
        (domArr[domArr.length-1] != "arpa") &&
        (domArr[domArr.length-1] != "coop") &&
        (domArr[domArr.length-1] != "aero"))
    {

        if (domArr[domArr.length-1].length<2 ||
            domArr[domArr.length-1].length>3)
        {
            alert("The address must end in a three-letter domain, or two letter country.");
            return false;
        }
    }

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

    return true;
}

function UPTvalidateform(thisform) {
    if(emailCheck(thisform.email.value)) {
        alert('Thank you for signing up!');
        return true;
    }
    return false;
}