// JavaScript Document
function emailcheck(emailval)
{
emailStr = emailval

var emailPat=/^(.+)@(.+)$/
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
var validChars="\[^\\s" + specialChars + "\]"
var firstChars=validChars
var quotedUser="(\"[^\"]*\")"
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
var atom="(" + firstChars + validChars + "*" + ")"
var word="(" + atom + "|" + quotedUser + ")"
var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
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]

// See if "user" is valid 
if (user.match(userPat)==null) {
    // user is not valid
    alert("The username doesn't seem to be valid.")
    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("Destination IP address is invalid!")
		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) {
   // the address must end in a two letter or three letter word.
   alert("The address must end in a three-letter domain, or two letter country.")
   return false
}

/* If it ends in a country code, we want to make sure there are at
   least 2 atoms preceding it (representing host and category (i.e.
   com, gov, etc.)) */
//if (domArr[domArr.length-1].length==2 && len<3) {
  // var errStr="This address ends in two characters, which is a country"
   //errStr+=" code.  Country codes must be preceded by "
  // errStr+="a hostname and category (like com, co, pub, pu, etc.)"
  // alert(errStr)
  // return false
//}
if (domArr[domArr.length-1].length==3 && len<2) {
   var errStr="This address is missing a hostname!"
   alert(errStr)
   return false
}
return true;
}