function emailCheck (emailStr) {
	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("Wrong email address.");
		return false;
	}

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


	if (user.match(userPat)==null) {
	    alert("Wrong user name");
	    return false;
	}

	var IPArray=domain.match(ipDomainPat);
	if (IPArray!=null) {
		  for (var i=1;i<=4;i++) {
		    if (IPArray[i]>255) {
		        alert("Wrong IP address");
				return false;
		    }
	    }
	    return true;
	}

	var domainArray=domain.match(domainPat);
	if (domainArray==null) {
		alert("Wrong domain name.");
	    return false;
	}

	if (len<2) {
	   var errStr="Domain name missing";
	   alert(errStr);
	   return false;
	}

	return true;
}