php使用cookie实现记住登录状态

//检查用户是否登录
function checklogin(){?
???? if(empty($_SESSION['user_info'])){??? //检查一下session是不是为空?
???? if(empty($_COOKIE['username']) || empty($_COOKIE['password'])){? //如果session为空,并且用户没有选择记录登录状?
???? header("location:login.php?req_url=".$_SERVER['REQUEST_URI']);? //转到登录页面,记录哀求的url,登录后跳转过去,用户体验好.?
}else{?? //用户选择了记住登录状态?
???? $user = getUserInfo($_COOKIE['username'],$_COOKIE['password']);?? //去取用户的个人资料?
???? if(empty($user)){??? //用户名密码不对没到取到信息,转到登录页面?
???? header("location:login.php?req_url=".$_SERVER['REQUEST_URI']);?
???? }else{?
???? $_SESSION['user_info'] = $user;?? //用户名和密码对了,把用户的个人资料放到session里面?
???? }?
???? }?
???? }?
}

username = trim($_POST['username']);?
$password = md5(trim($_POST['password']));?
$validatecode = $_POST['validateCode'];?
$ref_url = $_GET['req_url'];?
$remember = $_POST['remember'];?
?
$err_msg = '';?
if($validatecode!=$_SESSION['checksum']){?
$err_msg = "验证码不正确";?
}elseif($username=='' || $password==''){?
$err_msg = "用户名和密码都不能为空";?
}else{?
$row = getUserInfo($username,$password);?
?
if(empty($row)){?
$err_msg = "用户名和密码都不正确";?
}else{?
$_SESSION['user_info'] = $row;?
if(!empty($remember)){???? //如果用户选择了,记录登录状态就把用户名和加了密的密码放到cookie里面?
setcookie("username",$username,time()+3600*24*365);?
setcookie("password",$password,time()+3600*24*365);?
}?
if(strpos($ref_url,"login.php") === false){?
header("location:".$ref_url);?
}else{?
header("location:main_user.php");?
}?
}?
}

//退出登录
function logout(){?
unset($_SESSION['user_info']);?
if(!empty($_COOKIE['username']) || !empty($_COOKIE['password'])){?
setcookie("username",null,time()-3600*24*365);?
setcookie("password",time()-3600*24*365);?
}?
}

<?
//读取COOKIE的用户名和暗码的值即可
if($_COOKIE['uname']!=''){$CKUNAME =? $_COOKIE['uname'];}
if($_COOKIE['pwd']!=''){$CKPWD =? $_COOKIE['pwd'];}
echo $CKUNAME;
echo '<br>';
echo $CKPWD;
?>
<form id="form1" name="form1" method="post" action="">
??? <input type="text" name="uname" id="uname" value="<?=$CKUNAME;?>" /> <input
?????? type="password" name="pwd" id="pwd" value="<?=$CKPWD;?>" /> <input
?????? name="remember" type="checkbox" value="1" <? if($CKUNAME!=''){?>
?????? checked="checked" <? } ?> /> 记住我! <input type="submit" name="button"
?????? id="button" value="登录" />
</form>
<?
//登录,将用户名和暗码存入到COOKIE
if($_POST['button']!=''){
??? $uname = $_POST['uname'];
??? $pwd = $_POST['pwd'];
??? //如果输入的加密暗码和COOKIE中不一样,那么就加密
??? if($pwd!=$CKPWD){$pwd = md5($pwd);}
??? $remember = $_POST['remember'];
??? if($remember==1){
?????? setcookie("uname",$uname,time()+3600*24*30);
?????? setcookie("pwd",$pwd,time()+3600*24*30);
??? }
}
?>