在PHP中登录错误消息

Question

我是PHP代码的新手,如果用户输入了错误的用户标识或密码,我想在login.php中显示错误信息.我写了两页代码.login.php页面将用户名和密码提交给check.php页面.如果用户名和密码正确,则重定向到xyz.php else到登录页面.

login.php //登录页面

<form name="login" enctype="multipart/form-data" action="checkpage.php" method="post">
            <table border="0" cellpadding="0" cellspacing="0">
            <tr>
                <th>Username</th>
                <td><input type="text" name="username" value="sandeep" onfocus="this.value=''" class="login-inp" /></td>
            </tr>
            <tr>
                <th>Password</th>
                <td><input type="password" name="password" class="login-inp" /></td>
            </tr>
            <tr>
                <th></th>
                <td valign="top"><input type="checkbox" class="checkbox-size" id="login-check" /><label for="login-check">Remember me</label></td>
            </tr>
            <tr>
                <th></th>
                <td><input type="submit" class="submit-login"  /></td>
            </tr>

            <tr><th></th><td>w want to display error message here..</td></tr>

</table></form>

checkpage.php //连接页面

<?php
    session_start();
    //connecting to db
    $username=$_POST['username'];
    $pwd=$_POST['password'];
    $q="select *from xyz where username='$username' AND password='$pwd'";
    $qry=mysql_query($q);
    if(mysql_num_rows($qry)>0)
    {
        $_SESSION['username']=$username;
        echo "<script>window.open('xyz.php','_self')</script>"; 
        }
        else{

            header("location:login.php");

            }
?>

上面的代码工作正常但我想显示错误消息我怎么能显示错误消息.请指导我.

Answer 1

您可以在check.php脚本中将消息设置为session,然后在获取它后立即取消设置(AKA"read once"):

$_SESSION['message'] = 'Your message';

然后(在login.php中,您希望显示消息的位置):

if (isset($_SESSION['message']))
{
    echo $_SESSION['message'];
    unset($_SESSION['message']);
}