function ajax() {
	var ro;
	var browser = navigator.appName;
	if(browser == "Microsoft Internet Explorer"){
		ro = new ActiveXObject("Microsoft.XMLHTTP");
	}else{
		ro = new XMLHttpRequest();
	}
	return ro;
}

function checkLogin() {
	username = document.login.username.value;
	password = document.login.password.value;
	
	var ajx = new ajax;
	ajx.open('get', '../includes/ajax.php?action=login&username=' + username + '&password=' + password, true);
	ajx.onreadystatechange = function() {
		if(ajx.readyState == 4) {
			if(ajx.responseText == 'good') {
				window.location = 'main.php';
			} else {
				document.getElementById("loginMsg").innerHTML = 'login incorrect...';
			}
		}
	}
	ajx.send(null);
}