function ajax_check_login(){
	var xmlHttp;
	try {
		// Firefox, Opera 8.0+, Safari
		xmlHttp=new XMLHttpRequest();
	} catch (e) {
		// Internet Explorer
		try {
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {
				alert("Your browser does not support AJAX!");
				return false;
			}
		}
	}
	xmlHttp.onreadystatechange=function() {
		if(xmlHttp.readyState==4) {
			switch(xmlHttp.responseText){				
				case ("!password !username"):
					add_warning('warning_container','Don\'t forget to enter your username AND password!');
//					alert(xmlHttp.responseText);
					break;
				case ("!password"):
					add_warning('warning_container','Your password or username is wrong.');
//					alert(xmlHttp.responseText);
					break;
				case ("true"):
					document.login_check.submit();
					break;
				default:
					add_warning('warning_container',xmlHttp.responseText);
//					alert(xmlHttp.responseText);
					break;
			}
		}
		else{
			add_warning('warning_container','Loading...');
		}
	}
	var parameters = "username=" + document.getElementById('username').value + "&password=" + document.getElementById('password').value;
//	alert(parameters);
	xmlHttp.open("GET","check_login.php?"+parameters, true);
	xmlHttp.send(null);

}
function add_warning(x,y) {
	if(document.getElementById('warning')) {
		if(document.getElementById('warning').innerHTML == y){
			document.getElementById('warning').style.textDecoration = "blink";
			timed_blink();
			return;
		}
		else remove_warning();
	}
	var ni = document.getElementById(x);
	var newdiv = document.createElement('div');
	newdiv.setAttribute('id','warning');
	newdiv.setAttribute('class','warning');
	newdiv.innerHTML = y;
	ni.appendChild(newdiv);
}
function remove_warning() {
	var container = document.getElementById('warning_container');
	var warning = document.getElementById('warning');
	container.removeChild(warning);
}
function timed_blink(){
	var t1=setTimeout("document.getElementById('warning').style.textDecoration = 'none'",2000);
}
function check_enter_key(x){
	//alert("Test: "+x);
	if(x == 13) ajax_check_login();
}