var user=false;

registerCallback= function(xmldata) {
	if (xmldata) {
		var response= xmldata.getElementsByTagName('status').item(0).firstChild.data;

		if (response == 'Ok') {
		    user = true;
		} else {
			alert ('Username is not valid. Please re-enter your username.');
			user = false;
		}
	} else {
		alert('Unable to connect with the server. Please try again.');
	}
}

checkUserName= function(username) {
    if (username.value.length > 0) {
        AJAX.fetchXML ('/store/check_user.php', 'username='+username.value, registerCallback);
        return user;
    }
}

checkUserSubmit = function() {
    if (user == false) {
        alert ('Username is not valid. Please re-enter your username.');
    }
    return user;
}