//******************************************************************************************//
//********************* functions  for email-id validation ****************************//
//******************************************************************************************//
function isValidEmail(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 +")*$");
	var matchArray=emailStr.match(emailPat);
	if (matchArray==null) {
		return "Email address seems incorrect (check @ and .'s)";
		//alert("Email address seems incorrect (check @ and .'s)");
		//return false;
	}
	var user=matchArray[1];
	var domain=matchArray[2];
	// Start by checking that only basic ASCII characters are in the strings (0-127).
	for (i=0; i<user.length; i++) {
		if (user.charCodeAt(i)>127) {
			return "Ths username contains invalid characters.";
			//return false;
		}
	}
	for (i=0; i<domain.length; i++) {
		if (domain.charCodeAt(i)>127) {
			return "Ths domain name contains invalid characters.";
			//return false;
		}
	}
	if (user.match(userPat)==null) {
		return "The username doesn't seem to be valid.";
		//return false;
	}
	var IPArray=domain.match(ipDomainPat);
	if (IPArray!=null) {
		for (var i=1;i<=4;i++) {
			if (IPArray[i]>255) {
				return "Destination IP address is invalid!";
				//return false;
	   		}
		}
		return 0;
	}
	var atomPat=new RegExp("^" + atom + "$");
	var domArr=domain.split(".");
	var len=domArr.length;
	for (i=0;i<len;i++) {
		if (domArr[i].search(atomPat)==-1) {
			return "The domain name does not seem to be valid.";
			//return false;
	   }	
	}
	if (checkTLD && domArr[domArr.length-1].length!=2 && 
		domArr[domArr.length-1].search(knownDomsPat)==-1) {
		return "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) {
		return "This address is missing a hostname!";
		//return false;
	}	
	return 0;
}