
<!-- Changes:  Justin Wright -->
/* 1.1.3: Customized the functions to perform as I want, also added a couple
			new functions to help out ( allow recursive checking if a comma
			delimited string is passed in ).
*/
<!-- Changes:  Sandeep V. Tamhankar (stamhankar@hotmail.com) -->
/* 1.1.2: Fixed a bug where trailing . in e-mail address was passing
            (the bug is actually in the weak regexp engine of the browser; I
            simplified the regexps to make it work).
   1.1.1: Removed restriction that countries must be preceded by a domain,
            so abc@host.uk is now legal.  However, there's still the
            restriction that an address must end in a two or three letter
            word.
     1.1: Rewrote most of the function to conform more closely to RFC 822.
     1.0: Original  */

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin

/** Add trim() functionality to String instances. */
String.prototype.ltrim = function () { return this.replace(/^\s*/, "");}
String.prototype.rtrim = function () { return this.replace(/\s*$/, "");}
String.prototype.trim  = function () { return this.ltrim().rtrim(); }


// Added this function to loop through multiple email addresses entered
function emailCheck(emailAddressesStr) {
	var re = /[,\;]/g;
	var x = emailAddressesStr.split(re);
	for (var i=0;i<x.length;i++) {
		if( !emailAddrCheck(x[i].trim()) ) {
			return false;
		}
	}
	return true;
}

// check if str is empty
function isEmpty (str) {
	if (str == null || str == "")
		return true;
	else
		return false;
}

function emailAddrCheck (emailStr) {
/* The following pattern is used to check if the entered e-mail address
   fits the user@domain format.  It also is used to separate the username
   from the domain. */
var emailPat=/^(.+)@(.+)$/
/* The following string represents the pattern for matching all special
   characters.  We don't want to allow special characters in the address.
   These characters include ( ) < > @ , ; : \ " . [ ]    */
var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
/* The following string represents the range of characters allowed in a
   username or domainname.  It really states which chars aren't allowed. */
var validChars="\[^\\s" + specialChars + "\]"
/* The following pattern applies if the "user" is a quoted string (in
   which case, there are no rules about which characters are allowed
   and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
   is a legal e-mail address. */
var quotedUser="(\"[^\"]*\")"
/* The following pattern applies for domains that are IP addresses,
   rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
   e-mail address. NOTE: The square brackets are required. */
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
/* The following string represents an atom (basically a series of
   non-special characters.) */
var atom=validChars + '+'
/* The following string represents one word in the typical username.
   For example, in john.doe@somewhere.com, john and doe are words.
   Basically, a word is either an atom or quoted string. */
var word="(" + atom + "|" + quotedUser + ")"
// The following pattern describes the structure of the user
var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
/* The following pattern describes the structure of a normal symbolic
   domain, as opposed to ipDomainPat, shown above. */
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")


/* Finally, let's start trying to figure out if the supplied address is
   valid. */

/* Begin with the coarse pattern to simply break up user@domain into
   different pieces that are easy to analyze. */
var matchArray=emailStr.match(emailPat)
if (matchArray==null) {
  /* Too many/few @'s or something; basically, this address doesn't
     even fit the general mould of a valid e-mail address. */
	alert("Email address " + emailStr + " 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' portion of the email address " + emailStr + " doesn't seem to be valid.")
    return false
}

/* if the e-mail address is at an IP address (as opposed to a symbolic
   host name) make sure the IP address is valid. */
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 of email address " + emailStr + " is invalid!")
		return false
	    }
    }
    return true
}

// Domain is symbolic name
var domainArray=domain.match(domainPat)
if (domainArray==null) {
	alert("The domain name used in the email address " + emailStr + " doesn't seem to be valid.")
    return false
}

/* domain name seems valid, but now make sure that it ends in a
   three-letter word (like com, edu, gov) or a two-letter word,
   representing country (uk, nl), and that there's a hostname preceding
   the domain or country. */

/* Now we need to break up the domain to get a count of how many atoms
   it consists of. */
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 email address " + emailStr + " must end in a three-letter domain, or two letter country.")
   return false
}

// Make sure there's a host name preceding the domain.
if (len<2) {
   var errStr="The email address " + emailStr + " is missing a hostname!"
   alert(errStr)
   return false
}

// If we've gotten this far, everything's valid!
return true;
}
//  End -->