function emailCheck(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.");
		return false;
	}

	var user=matchArray[1];
	var domain=matchArray[2];

	for(i = 0; i < user.length; i++)
	{
		if(user.charCodeAt(i) > 127)
		{
			alert("The email username contains invalid characters.");
			return false;
		}
	}

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

	if(user.match(userPat) == null)
	{
		alert("The email username is invalid.");
		return false;
	}

	var IPArray = domain.match(ipDomainPat);

	if(IPArray != null)
	{
		for(var i = 1; i <= 4; i++)
		{
			if(IPArray[i] > 255)
			{
				alert("The email destination IP address is invalid.");
				return false;
			}
		}
		return true;
	}

	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 email domain name is invalid.");
			return false;
		}
	}

	if(checkTLD && domArr[domArr.length-1].length !=2
		&& domArr[domArr.length-1].search(knownDomsPat) == -1)
	{
		alert("The email address must end in a valid email suffix.");
		return false;
	}

	if(len < 2)
	{
		alert("The email address is missing a hostname.");
		return false;
	}

	return true;
}