Untitled

<html>
<head>
	<title>login</title>
	<script type="text/javascript" >
		function id(id){
			return document.getElementById(id);
		}
		function setCookie(c_name,value,expiredays){
			var exdate=new Date();
			exdate.setDate(exdate.getDate()+expiredays);
			document.cookie=c_name+ "=" +escape(value)+
			((expiredays==null) ? "" : ";expires="+exdate.toUTCString());
		}
		function login(form){
			if(form.username.value == ""){
				id("note1").textContent="please enter the username";
				form.username.focus();
				return;
			}
			else
				id("note1").textContent="";
			if(form.password.value == ""){
				id("note2").textContent="please enter the password";
				form.password.focus();
				return;
			}
			else
				id("note2").textContent="";

			var ajax=new XMLHttpRequest();
			ajax.onreadystatechange = function(){
				if(this.readyState == 4 && this.status == 200){
					var check = this.responseText;
					alert(check);
					if(check == "true"){
						setCookie('username',form.username.value,10);
						location.replace("index.html");
					}
					else if(check == "false"){
						id("response").textContent="wrong username or password";
						return;
					}
					else{
						id("response").textContent="...error";
						return;
					}
				}
			}
			ajax.open("POST","login.php");
			ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
			ajax.send("username="+form.username.value+"&password="+form.password.value);
		}

	</script>
</head>
<body>
	<form>
	<fieldset>
	<legend>login</legend>
	username:<input type="text" name="username" /><span id="note1"></span><br />
	password:<input type="password" name="password" /><span id="note2"></span><br />
	<input type="button" value="login" onclick="login(this.form)"/>
	<p id="response"></p>
	</fieldset>
	</form>
	<a href="register.html">register</a>
	<a href="index.html">index</a>
</body>
</html>