
<!-- Changes:  Sandeep V. Tamhankar (stamhankar@hotmail.com) -->
<!-- @author extendedEmailCheck function Andrew Wagner -->

/*
   4-mar-04  [DT] Allow four letter end words (eg .info)
   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
function emailCheck (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 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
}

/* 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 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
}

/* 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>4) {
   // 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
}

// Make sure there's a host name preceding the domain.
if (len<2) {
   //alert("This address is missing a hostname.")
   return false
}

// If we've gotten this far, everything's valid!
return true;
}

function extendedEmailCheck (listStr, idStr) {

   var retmessage = "";
   if (listStr == "")
   {
        if (idStr == "single") {
		   retmessage = "Please enter your email address.\n";
	    }
		if (idStr == "list") {
		   retmessage = "Please enter your friend's email address.\n";
		}
   }
   else {
      var listStrArray = listStr.split(/\;|,|\n|\r|\f|\t| /);
	  if (listStrArray.length == 0) {
          if (idStr == "single") {
		     retmessage = "Please enter your email address.\n";
	      }
		  if (idStr == "list") {
		     retmessage = "Please enter your friend's email address.\n";
		  }
	  }
      else {
          var count = 0;
		  var countblank = 0;
	      while (count + countblank < listStrArray.length) {
	          if (listStrArray[count + countblank].length > 0) {
			     if (emailCheck (listStrArray[count + countblank]) != true) {
		            if (idStr == "single") {
					   retmessage = "Your email address appears to be invalid.\n";
					}
					if (idStr == "list") {
					   retmessage = "One or more of your friends' email addresses appear to be invalid.\n";
					}
		            count = listStrArray.length + 1;
		         }
		         else {
		            count = count + 1;
		         }
	         }
			 else {
			    countblank = countblank + 1;
			}
	     }
	  }
   }
   
   if (idStr == "single" && retmessage == "") {
      if (count > 1) {
        retmessage = "You have entered more than one email address for yourself.\n";
      }
	  if (count == 0) {
	    retmessage = "Please enter your email address.\n";
	  }
   }
   if (idStr == "list" && retmessage == "") {
     if (count == 0) {
	   retmessage = "Please enter your friend's email address.\n";
	 }
   }

   return retmessage;
}	
//  End -->