function emailCheck (emailStr) {
var emailPat=/^(.+)@(.+)$/
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]" // special chars: ( ) < > @ , ; : \ " . [ ]
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("Please specify a valid email address.");
  return false;
}

var user=matchArray[1]
var domain=matchArray[2]

// See if "user" is valid
if (user.match(userPat)==null) {
    alert("Please specify a valid email address.");
    return false
}

var IPArray=domain.match(ipDomainPat)
if (IPArray!=null) {
    // this is an IP address
          for (var i=1;i<=4;i++) {
            if (IPArray[i]>255) {
                alert("Please specify a valid email address.");
                return false
            }
    }
    return true
}

// Domain is symbolic name
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].length<2 || 
    domArr[domArr.length-1].length>3) {
   alert("Please specify a valid email address.");
   return false
}

// Make sure there's a host name preceding the domain.
if (len<2) {
   var errStr="This address is missing a hostname!"
   alert(errStr)
   return false
}

// If we've gotten this far, everything's valid!
return true;
}
//  End -->