未定义的索引

Question

注意：未定义的索引：用户名在C：\ wamp \ www \ CodeCanyon \ MCBuddy \ Global.php在第5行 注意：未定义的索引：C：\ wamp \ www \ CodeCanyon \ MCBuddy \ Global中的密码在线.PHP 6

这里是我的Global.php代码：

session_id(); 
session_start(); 
ob_start(); 
$loggedIn = $_SESSION['Username']; 
$Password = $_SESSION['Password']; 
$CurrentTime = time(); 
// MySQL Database Conection Information 
define("DBHost", "localhost"); // MYSQL Database Host 
define("DBUsername", "root"); // MYSQL Database Username 
define("DBPassword", ""); // MYSQL Database Password 
define("Database", "mcbuddy"); // MYSQL Database Name 
// Establish Connection to MYSQL Database 
$db = new mysqli(DBHost, DBUsername, DBPassword, Database); 
if ($db->connect_errno) { 
    echo "Failed to connect to MySQL: (" . $db->connect_errno . ") " . $db->connect_error; 
} 

我login.php中（我认为错误是在这里）

<?php 
require 'Global.php'; 
?> 
<div class='well'> 
<div style='text-align:center'> 
<h2> Sign In </h2> 
<center> 
<p id='errorMsg' style='background-color: #D11124; width:300px; color:white; text-align:center;'/> 
<form action='' method='POST'> 
<input type='text' name='Username' placeholder='Username'> <br /> 
<input type='password' name='Password' placeholder='Password'> <br /> 
<input class='btn btn-xlarge' type='submit' name='signin' value='Sign In'> 
</form> 
</div> 
</div> 

<?php 
if(isset($_REQUEST['signin'])) { 
$Username = htmlspecialchars(strip_tags($_REQUEST['Username'])); 
$Password = htmlspecialchars(strip_tags($_REQUEST['Password'])); 
$p1 = md5($Password); 
$UserInfo = $db->query("SELECT * FROM users WHERE Username='$Username'"); 
$UserI = $UserInfo->fetch_array(MYSQLI_BOTH); 

    if(empty($Password) || $Password == '') { 
    echo " 
    <script type='text/javascript'> 
       document.getElementById('errorMsg').innerHTML = 'Password is empty!'; 
    </script> 
    "; 
    } 
    elseif(empty($Username) || $Username == '') { 
    echo " 
    <script type='text/javascript'> 
       document.getElementById('errorMsg').innerHTML = 'Username is empty!'; 
    </script> 
    "; 
    } 
     elseif($UserI['Password'] != $p1) { 
     echo " 
     <script type='text/javascript'> 
       document.getElementById('errorMsg').innerHTML = 'Incorrect username/password'; 
     </script> 
    "; 

     } else { 
     $_SESSION['Username']=$Username; 
     $_SESSION['Password']=$Password; 
     } 
} 

Answer 1

您还可以设置会话变量为null：

//add line 4: 
$_SESSION['Username'] = null; 
$_SESSION['Password'] = null;