<?php 
    if(isset($_POST['name'])||isset($_POST['pass'])){ 
        //如果有表单有提交 
        //检测表单中需要的值 
        if(empty($_POST['name'])){ 
            die("请输入用户名！"); 
        } 
        if(empty($_POST['pass'])){ 
            die("请输入密码！"); 
        } 
        //设置数据库变量 
        $host = "localhost"; 
        $user = "root"; 
        $pass = "zq19890319"; 
        $db = "cookie"; 
        //打开连接 
        $connection = mysql_connect($host, $user, $pass) or die("Unable to connect!"); 
        //选择一个数据库 
        mysql_select_db($db) or die("Unable to select database!"); 
        //建立一个查询 
        $query = "SELECT * FROM users WHERE name = '".$_POST['name']."' AND pass = SHA1('".$_POST['pass']."')"; 
        //执行一个查询 
        $result = mysql_query($query) or die("Error in query:$query." . mysql_error()); 
        //是否有记录集返回 
        if(mysql_num_rows($result) == 1){ 
            //如果有一行记录返回 
            //表示验证已经通过 
            //建立一个session，设置一个登陆标记为1，并将当前用户名保存在cookie中 
            session_start(); 
            $_SESSION['auth'] = 1; 
            setcookie("username", $_POST['name'], time()+(84600*30)); 
            echo "用户访问已经授权！"; 
        }else{ 
            echo "错误的用户名或密码！"; 
        } 
        //释放记录集 
        mysql_free_result($result); 
        //关闭数据库 
        mysql_close($connection); 
    } 
    else{ 
        //如果没有表单提交，则显示一个HTML表单 
    ?> 
    <html> 
    <head></head> 
    <body> 
        <center> 
            <form method="post" action=""> 
            用户名<input type="text" name="name" value="<?php echo $_COOKIE['username'];?>" /> 
            <p /> 
            密码<input type="password" name="password" /> 
            <p /> 
            <input type="submit" name="submit" value="登陆" /> 
            </form> 
        </center> 
    </body> 
<?php 
    } 
?>