登录系统：会话开始的问题

Question

I have a login system which checks for the correct login details like below :

    <?php
    @session_start();
    require_once "connection.php";
    $Username=$_POST['uname'];
    $Password=$_POST['pass'];

    $encrypt_password=md5($Password);
    //echo $encrypt_password; 

    $Username=stripslashes($Username);
    $Password=stripslashes($Password);
    $Username = mysql_real_escape_string($Username);
    $Password = mysql_real_escape_string($Password);

    $sql="SELECT * FROM loginlist WHERE username='$Username' and password='$encrypt_password'";
    $query=mysql_query($sql) or die(mysql_error());
    $Count=mysql_num_rows($query);
    if($Count == 1)
    {
        session_register(myusername);
        session_register(mypassword);
        $_SESSION['uname']=$Username;
        $_SESSION['pass']=$Password;

        header("location:controlpanel.php");
    }
    else
    {
        echo 'wrong user name or password';
    }
?>

if the login details are correct it will transfer to the controlpanel.php, I have the below code at the start of controlpanel.php

    @session_start();
    if(!isset($_SESSION['uname']))
       echo"<script>window.location='thisisthesystem.php';</script>";
    else

but every time I try to login (with correct login details) it throws me back to the login page. Please let me know what's going on wrong there :

Thanks in advance.

Answer 1

You should lookup at the isset more.

ISSET checks the variable to see if it has been set, in other words, it checks to see if the variable is any value except NULL or not assigned a value. ISSET returns TRUE if the variable exists and has a value other than NULL. That means variables assigned a " ", 0, "0", or FALSE are set, and therefore are TRUE for ISSET.

if ( isset($Variable)){
  //this will be true if $Variable will have some value
}else {
//this is false if $Variable will be empty
}

So remove ' ! ' From if as I have said in comment section

See more about Isset