/******************************************************************************
email functions
---------------

The software and related user documentation are protected under
copyright laws.
*******************************************************************************/
<!--
/*********************************************************
Name  : 
Descr : 
Input : 
Output: 
Usage : 
*********************************************************/
function is_email(emailStr)
{
	var checkTLD=1;
	var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
	var emailPat=/^(.+)@(.+)$/;
	var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
	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("Email address seems incorrect (check @ and .'s)");
		return false;
	}
	var user=matchArray[1];
	var domain=matchArray[2];
	
	for (i=0; i<user.length; i++) {
		if (user.charCodeAt(i)>127) {
			//alert("Ths username contains invalid characters.");
			return false;
		}
	}
	
	for (i=0; i<domain.length; i++) {
		if (domain.charCodeAt(i)>127) {
			//alert("Ths domain name contains invalid characters.");
			return false;
		}
	}
	
	if (user.match(userPat)==null) {
		//alert("The username doesn't seem to be valid.");
		return false;
	}
	
	var IPArray=domain.match(ipDomainPat);
	if (IPArray!=null) {
		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.  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("The 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("The address 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("This address is missing a hostname!");
		return false;
	}
	
	// If we've gotten this far, everything's valid!
	return true;
}//is_email()
//-->