<!--
function emailCheck (emailStr) {

/* The following variable tells the rest of the function whether or not
to verify that the address ends in a two-letter country or well-known
TLD.  1 means check it, 0 means don't. */
var checkTLD=1;


/* The following is the list of known TLDs that an e-mail address must end with. */
var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;


/* 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("\"" + emailStr + "\"" + " seems incorrect (check @ and .'s)");
	return false;
}
var user=matchArray[1];
var domain=matchArray[2];

var dots = 0;

// Start by checking that only basic ASCII characters are in the strings (0-127).


 for (i=0; i<user.length; i++) {
	//if (user.charCodeAt(i)>127) {
	 if ( user.charCodeAt(i) == 39 ||(user.charCodeAt(i)>44 && user.charCodeAt(i)<47) || user.charCodeAt(i) == 95 || (user.charCodeAt(i)>47 && user.charCodeAt(i)<58) || (user.charCodeAt(i)>64 && user.charCodeAt(i)<91) || (user.charCodeAt(i)>96 && user.charCodeAt(i)<123)) {
		 // do nothing 
		 
		}else{
		alert("\"" + emailStr + "\"" + " username contains invalid characters.");
		return false;
		}
	}

for (i=0; i<domain.length; i++) {
	if (domain.charCodeAt(i)>127) {
		alert("\"" + emailStr + "\"" + " domain name contains invalid characters.");
		return false;
   	}
   			
}


// See if "user" is valid
if (user.match(userPat)==null) {
	// user is not valid
	alert("\"" + emailStr + "\"" + " 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("\"" + emailStr + "\"" + " destination IP address is invalid!");
			return false;
   		}
	}
	return true;
			
}


// Domain is symbolic name.  Check if it's valid.
var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;
for (i=0;i<len;i++) {
	if (domArr[i].search(atomPat)==-1) {
		alert("\"" + emailStr + "\"" + " domain name does not seem to be valid.");
		return false;
   	}
   			
}


/* domain name seems valid, but now make sure that it ends in a
known top-level domain (like com, edu, gov) or a two-letter word,
representing country (uk, nl), and that there's a hostname preceding
the domain or country. */
if (checkTLD && domArr[domArr.length-1].length!=2 &&
	domArr[domArr.length-1].search(knownDomsPat)==-1) {
	alert("\"" + emailStr + "\"" + " must end in a well-known domain or two letter " + "country.");
	return false;
			
}


// Make sure there's a host name preceding the domain.
if (len<2) {
	alert("\"" + emailStr + "\"" + " is missing a hostname!");
	return false;
			
}


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


/*
	This function performs the same validation, but returns a string with error message so that
	an alert is not generated
*/
function emailCheckStr (emailStr) {

/* The following variable tells the rest of the function whether or not
to verify that the address ends in a two-letter country or well-known
TLD.  1 means check it, 0 means don't. */
var checkTLD=1;
var validationString = "";

/* The following is the list of known TLDs that an e-mail address must end with. */
var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;


/* 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("\"" + emailStr + "\"" + " seems incorrect (check @ and .'s)");
	validationString = emailStr + " seems incorrect (check @ and .'s)";
	return validationString;
}
var user=matchArray[1];
var domain=matchArray[2];


// Start by checking that only basic ASCII characters are in the strings (0-127).

for (i=0; i<user.length; i++) {
	if (user.charCodeAt(i)>127) {
		//alert("\"" + emailStr + "\"" + " username contains invalid characters.");
		validationString = emailStr + " username contains invalid characters."
		return validationString;
   	}
}

for (i=0; i<domain.length; i++) {
	if (domain.charCodeAt(i)>127) {
		//alert("\"" + emailStr + "\"" + " domain name contains invalid characters.");
		validationString = emailStr + " domain name contains invalid characters."
		return validationString;
   	}
}


// See if "user" is valid
if (user.match(userPat)==null) {
	// user is not valid
	//alert("\"" + emailStr + "\"" + " username doesn't seem to be valid.");
	validationString = emailStr + " username doesn't seem to be valid."
	return validationString;
}


/* 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("\"" + emailStr + "\"" + " destination IP address is invalid!");
			validationString = emailStr + " destination IP address is invalid!"
			return validationString;
   		}
	}
	return validationString;
}


// Domain is symbolic name.  Check if it's valid.
var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;
for (i=0;i<len;i++) {
	if (domArr[i].search(atomPat)==-1) {
		//alert("\"" + emailStr + "\"" + " domain name does not seem to be valid.");
		validationString = emailStr + " domain name does not seem to be valid."
		return validationString;
   	}
}


/* domain name seems valid, but now make sure that it ends in a
known top-level domain (like com, edu, gov) or a two-letter word,
representing country (uk, nl), and that there's a hostname preceding
the domain or country. */
if (checkTLD && domArr[domArr.length-1].length!=2 &&
	domArr[domArr.length-1].search(knownDomsPat)==-1) {
	//alert("\"" + emailStr + "\"" + " must end in a well-known domain or two letter " + "country.");
	validationString = emailStr + " must end in a well-known domain or two letter " + "country."
	return validationString;
}


// Make sure there's a host name preceding the domain.
if (len<2) {
	//alert("\"" + emailStr + "\"" + " is missing a hostname!");
	validationString = emailStr + " is missing a hostname!"
	return validationString;
}


// If we've gotten this far, everything's valid!
return validationString;
}

//-->