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 (thisform.val_72273.value==""){  
alert("Please enter a value for Name");
return(true);}
  if (emailCheck(thisform.email.value)) 
  { 

        if (document.getElementById('unsubscribe') 
            && !document.getElementById('unsubscribe').checked) {
        alert('Thank you for signing up!');
        } else {
            alert('Thank you for signing up!');
        }
    return false;
  }
  else
  {
    return true;
  }
}