function arkLoginUser() {

	// login user

	if ($("#arkLoginUsername").val() != "" && $("#arkLoginPassword").val() != "") {
	
		$("#arkLoginForm").submit();
	
	} else {
	
		arkNotify("Missing fields in the form");
			
	}

}

function arkGetResponseMessage(string) {

	// decode backend response message

	return string.between("<message>", "</message>");

}

function arkGetResponseStatus(string) {

	// decode backend response status

	return string.between("<status>", "</status>");

}

String.prototype.between = function(prefix, suffix) {

	string = this;
	
	var i = string.indexOf(prefix);
	
	if (i >= 0) {
	
		string = string.substring(i + prefix.length);
		
	} else {
	
		return "";
		
	}
	
	if (suffix) {
	
		i = string.indexOf(suffix);
		
		if (i >= 0) {
		
			string = string.substring(0, i);
			
		} else {
		
			return "";
			
		}
		
	}
	
	return string;
	
}

function arkNotify(string) {

	// popup notifier with message

	$(".arkNotifier").fadeOut(300, function() {

		$(".arkNotifier").html(string);

		$(".arkNotifier").fadeIn(300);

	});

}