var http_request = false;
var objinner;
var dangtai;

//Tao 1 request:
function makeRequest(url, functionName, httpType, sendData,cnobj) {
	
	if(url.indexOf('?')>=0)
		url=url+"&&rd="+Math.random();
	else
		url=url+"?rd="+Math.random();
	
	objinner=cnobj;
	if (httpType=="GET")
	{
		dangtai=cnobj;
	}
 	http_request = false;
	if (!httpType) httpType = "GET";

	if (window.XMLHttpRequest) { // Non-IE...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType('text/plain');
		}
	} else if (window.ActiveXObject) { // IE
		try {
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				http_request = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {}
		}
	}

	if (!http_request) {
		alert('Cannot send an XMLHTTP request');
		return false;
	}

	//Khai bao nhung gi se dien ra luc nhan duoc response (dap tra) tu Server
	var changefunc="http_request.onreadystatechange = "+functionName;
	eval (changefunc);

	http_request.open(httpType, url, true);
	
	//http_request.onreadystatechange = alertContents;
	
	if(httpType=="POST")
	{
	http_request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
	//alert(url);
	}
	else
	http_request.setRequestHeader("Content-Type","text/html; charset=UTF-8");	
	http_request.setRequestHeader("Cache-Control","no-cache");

	http_request.send(sendData);
	
}

//Du lieu tra ve sau khi xu ly o Server
function start_return() {
	if (http_request.readyState == 4)
	 {
		if (http_request.status == 200)
		{
		var messagereturn = http_request.responseText;
		
		//alert(messagereturn);
		//Du lieu tra ve se inner vao obj co ten objinner
		objinner.innerHTML=messagereturn;

		}
		else
		{
			alert(http_request.status);
		}
	}	
}

function start_return_checkuser() {
	if (http_request.readyState == 4)
		 {
			if (http_request.status == 200)
			{
				var messagereturn = http_request.responseText;
				var Submit = document.getElementById("ok");
			//alert(messagereturn);
			//Du lieu tra ve se inner vao obj co ten objinner
				//objinner.innerHTML=messagereturn;
			
				if(messagereturn == 1)
				{
					objinner.innerHTML = "<br><span style='color:red;'>Username này đã có người dùng</span>";
					document.getElementById("u").focus();
					document.getElementById("u").select();
					Submit.disabled = true;
					Submit.style.color = '#000000';
					Submit.style.cursor = 'default';
				}
				if(messagereturn == 0)
				{
					objinner.innerHTML = "<br><span style='color:blue;'>Bạn có thể sử dụng Username này</span>";
					Submit.disabled = false;
					Submit.style.color = '#FFFFFF';
					Submit.style.cursor = 'pointer';
				}

			}		
		}	

}


//CHANGE IMAGE MA BAO VE
function start_return_image() {
	if (http_request.readyState == 4)
		 {
			if (http_request.status == 200)
			{
			var messagereturn = http_request.responseText;
			
			//alert(messagereturn);
			//Du lieu tra ve se inner vao obj co ten objinner
			objinner.src = messagereturn+Math.random();
			

			}		
		}	
}

//Load lai trang theo ajax:
function loadimagemoi(url,obj)
{
			 //ajaxL.background="www/bgroundran/"+Math.round(Math.random()*44)+".jpg";
	var ip=url.indexOf("#");
	ip++;
	var url=url.substr(ip,url.length);
	//url=url.replace("&&","?");
	return makeRequest(url,"start_return_image","GET",null,obj);
}
//END CHANGE IMAGE MA BAO VE

function filldata(chuoinoidung)
{
	for(var k=0; k<chuoinoidung.length;k++)
	{
		if(chuoinoidung.charAt(k)=="&")
		{
		truoc=chuoinoidung.substr(0,k);
		sau=chuoinoidung.substr(k+1,chuoinoidung.length);
		giua="[va]";
		chuoinoidung=truoc+giua+sau;
		}
		if(chuoinoidung.charAt(k)=="+")
		{
		truoc=chuoinoidung.substr(0,k);
		sau=chuoinoidung.substr(k+1,chuoinoidung.length);
		giua="[cong]";
		chuoinoidung=truoc+giua+sau;
		}
		if(chuoinoidung.charAt(k)=="'")
		{
		truoc=chuoinoidung.substr(0,k);
		sau=chuoinoidung.substr(k+1,chuoinoidung.length);
		giua="`";
		chuoinoidung=truoc+giua+sau;
		}
		if(chuoinoidung.charAt(k)=="<")
		{
		truoc=chuoinoidung.substr(0,k);
		sau=chuoinoidung.substr(k+1,chuoinoidung.length);
		giua="[b]";
		chuoinoidung=truoc+giua+sau;
		}
		if(chuoinoidung.charAt(k)==">")
		{
		truoc=chuoinoidung.substr(0,k);
		sau=chuoinoidung.substr(k+1,chuoinoidung.length);
		giua="[l]";
		chuoinoidung=truoc+giua+sau;
		}
		if(chuoinoidung.charAt(k)=="%")
		{
		truoc=chuoinoidung.substr(0,k);
		sau=chuoinoidung.substr(k+1,chuoinoidung.length);
		giua="[phantram]";
		chuoinoidung=truoc+giua+sau;
		}
	
	}
	return chuoinoidung;
}

function checkMail(email){
	var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if(filter.test(email))return true;
	else return false;
	}
	
function clearText(field)
	{
    	if (field.defaultValue == field.value) field.value = '';
   	    else if (field.value == '') field.value = field.defaultValue;
	}