// JavaScript Document
//Create Microsoft.XMLHTTP Object
function makeObject(){
var x; 
var browser = navigator.appName; 
//detect the client browser
if(browser == "Microsoft Internet Explorer"){
x = new ActiveXObject("Microsoft.XMLHTTP");
}else{
x = new XMLHttpRequest();
}
return x;
}

//call the function makeObject()


//function send request_user_ajax
function isUser(username){
	
	var request_user_ajax = makeObject();
	
	document.getElementById('signup_check').style.display='block';
	var url = "signup.php?action=chkuser&username="+username;
	request_user_ajax.open('get',url,true);
	request_user_ajax.onreadystatechange = isUserDone; 
	request_user_ajax.send('');
	
	
	     function isUserDone(){
	        if(request_user_ajax.readyState == 4 || request_user_ajax.readyState == "complete"){ 
				  var answer = request_user_ajax.responseText;
				  document.getElementById('signup_check').style.display='none';
				  alert(answer);
			}
          }

	
}
//function send data