Question

我正在尝试Echo $ _SESSION [“myusername”]。我可以登录我的页面，但我不能Echo myusername。我收到以下错误。未定义的变量：C：....中的myusername

checklogin.php页面如下

<?php

ob_start();
$host="localhost"; // Host name
$username="root"; // Mysql username
$password=""; // Mysql password
$db_name="techdb"; // Database name
$tbl_name="members"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];

$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);

$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 1 row
if($count==1){
  $_SESSION['myusername']=$myusername;
  $_SESSION['mypassword']=$mypassword;

  header("location:technicianform.php");
} else {
  echo "Wrong Username or Password";
}

ob_end_flush();
?>

我的technicianform.php页面是

<?php
session_start();

if( isset($_SESSION['$myusername']) ){
  header("location:checklogin.php");
}
?>

<html>
<body>
  <p>Login Successful</p>
  <?php echo $_SESSION["myusername"]; ?>
  <p><br/>

  <br/><br/><a href='Logout.php'>Click here to log out</a></p>
</body>
</html>

登录过程有效但我似乎无法回显myusername。非常感谢您的帮助。

Answer 1

要在checklogin.php文件中创建会话变量，您需要开始会话。

您正在获取未定义的索引通知，因为您缺少以下内容：

session_start(); // add in checklogin.php file

第二个问题是：

$_SESSION['$myusername']

应该是：

$_SESSION['myusername']

旁注：

停止使用mysql_*扩展名，在PHP 7中弃用并关闭。使用mysqli_*或PDO。

Answer 2

只需删除此$符号。

变化：

 if( isset($_SESSION['$myusername']) )

要

 if( isset($_SESSION['myusername']) )

另外，在checklogin.php中你需要提到

session_start();

希望这有帮助。

和平！的xD

Answer 3

    **Try This.**





login.php

    <?php

     session_start();
     $host="localhost"; // Host name
     $username="root"; // Mysql username
     $password=""; // Mysql password
     $db_name="techdb"; // Database name
     $tbl_name="members"; // Table name

      // Connect to server and select databse.
       mysql_connect("$host", "$username", "$password")or die("cannot connect");
      mysql_select_db("$db_name")or die("cannot select DB");

    if(isset($_POST['submit'])){
     $myusername=trim($_POST['myusername']);
     $mypassword=trim($_POST['mypassword']);




       $sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
       $result=mysql_query($sql);

       // Mysql_num_row is counting table row
      $count=mysql_num_rows($result);

      // If result matched $myusername and $mypassword, table row must be 1 row

      if($count== 1){


       $_SESSION['myusername']=$myusername;
       $_SESSION['mypassword']=$mypassword;

       header("location:technicianform.php");
       }
       else {
       echo "Wrong Username or Password";
       }

    }
       ?>



       <form method="post">
     <label>username :</label><input type="text" name="myusername"></br>
      <label>password :</label>  <input type="password" name="mypassword"></br>
         <input type="submit" name="submit" value="submit">
       </form>`

technicianform.php

<?php
   session_start();

   if( isset($_SESSION['$myusername']) ){

   header("location:checklogin.php");

   }
   ?>

   <html>
   <body>
   <p>Login Successful</p>
   <?php

    echo $_SESSION["myusername"];

    ?>
    <p><br/>

    <br/><br/><a href='Logout.php'>Click here to log out</a></p>
    </body>
    </html>

会话myusername

3 个答案: