無法從PHP

Question

顯示HTML代碼錯誤的憑據錯誤我有一個問題 這是我的index.php文件

<section class="main"> 
    <form class="form-3" method="post" action="back/login.php"> 
     <p class="clearfix"> 
      <input type="text" name="username" id="username" placeholder="username"> 
      <label for="login">username</label> 
     </p> 
     <p class="clearfix"> 
      <input type="password" name="password" id="password" placeholder="password"> 
      <label for="password">password</label> 
     </p> 

     <p class="clearfix"> 
      <input type="submit" name="submit" value="Sign In"> 
     </p> 

     <p class="clearfix"> 
      <label for="remember">remember me</label> 
      <input type="checkbox" name="remember" id="remember"> 
     </p> 
    </form>​ 

    * 
    <div class="error"><?php echo $error;?></div> 
    * 
</section> 

，這是我的login.php文件

<?php 

session_start(); 
include("connection.php"); 

$error = ""; 
if (isset($_POST["submit"])) { 
    if (empty($_POST["username"]) || empty($_POST["password"])) 
     $error = "Both fields are required."; 

    else { 
     $username = $_POST['username']; 
     $password = $_POST['password']; 
     $username = stripslashes($username); 
     $password = stripslashes($password); 
     $username = mysqli_real_escape_string($db, $username); 
     $password = mysqli_real_escape_string($db, $password); 
     $password = md5($password); 

     $sql = "SELECT uid FROM users WHERE username='$username' and password='$password'"; 
     $result = mysqli_query($db,$sql); 
     $row = mysqli_fetch_array($result,MYSQLI_ASSOC); 
     $login_user = $username; 

     if (mysqli_num_rows($result) == 1) { 
      $_SESSION['username'] = $login_user; 
      header("location: home.php"); 
     } 
     else { 
      $error = "Incorrect username or password."; 
      header("location: ../index.php"); 
     } 
    } 
} 

但我的$在HTML代碼錯誤不起作用...

我的意思是，當我把不正確的密碼和用戶名，它只是重定向我的index.php頁面，裏面沒有任何錯誤...

也是我的login.php文件包含在我的index.php

Answer 1

這是因爲$錯誤變量是的login.php文件中並沒有的index.php。

基本上有index.php文件中沒有名爲$ error的變量。

一個簡單的方法做你想要做的是重定向到的index.php從的login.php與像一個錯誤變量是什麼：

header("location: ../index.php?error=1"); 

，然後內的index.php，使用開關外殼的錯誤，如：

if(isset($_GET['error'])) { 
    $error_id = $_GET['error']; 
    switch($error_id) { 
    case 1: 
     $error = "Incorrect username or password."; 
    break; 
    } 
} 

我希望幫助！