// Create by Yung, LK

/************************************************************** init xml object*/
var request = false;
try {
 request = new XMLHttpRequest();
} catch (trymicrosoft) {
 try {
	 request = new ActiveXObject("Msxml2.XMLHTTP");
 } catch (othermicrosoft) {
	 try {
		 request = new ActiveXObject("Microsoft.XMLHTTP");
	 } catch (failed) {
		 request = false;
	 }  
 }
}
if (!request) {
 alert("Error initializing XMLHttpRequest!");
}

/**************************************************************/
function emailValidator( value, fieldname ) {
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(value)) {
		return true;
	} else {
		var message = "Only following characters is acceptable for use: \na-z  A-Z  0-9  _ -";
		alert(fieldname + ' : Incorrect email address format.\n\n' + message);
		return false;
	}
}

function numberValidator( value, fieldname ) {
	var filter  = /^[0-9]{1,}$/;
	if (filter.test(value)) {
		return true;
	} else {
		var message = "Only following characters is acceptable for use: \n0-9";
		alert(fieldname + ' : Incorrect input format.\n\n' + message);
		return false;
	}
}

function requiredFieldValidator( value, fieldname ) {
	var filter  = /^([a-zA-Z0-9])+$/;
	if (filter.test(value)) {
		return true;
	} else {
		var message = "Only following characters is acceptable for use: \na-z  A-Z  0-9";
		alert(fieldname + ' : Incorrect input format.\n\n' + message);
		return false;
	}
}


function countGame( gameid ) {
	var url = "/student/action/count_game.php?gameid=" + gameid;
	request.open("GET", url, true);
	request.onreadystatechange = updateMessage;
	request.send(null);
}

function updateMessage() {
	if (request.readyState == 4) {
		if (request.status == 200) {
		//	alert("Server is done!");
		}
		else if (request.status == 404) {
			alert("Request URL does not exist");
		}
	}
}


String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g, ''); }