How to display popup message when logged out user try to vote ?

0 0 1 minute read

How users logged in or logged out is detected?
When a user satisfies the conditions for login his status changes to logged in. For a website or system to understand that a user is logged in usually a $_SESSION[‘ ‘] variable is set as soon as the user logs in. This variable when set helps the website to recognize that a user is present and provides access to all the available functionalities.

For example, when we log into a website it usually displays messages like:

WELCOME Name_Of_The_user

So how does this happen?
When users login to a website, the website recognizes the user and extracts the necessary information about the user from the database for proper functioning. At the same time $_SESSION[‘ ‘] variable is set to help every page on the website be aware that a user is in session or logged in.

So, if a user is not logged in, the $_SESSION[‘ ‘] variable is not set. To display a popup message when a user is logged out we simply need to run an if loop. When a user clicks on a button direct them to a PHP file or a function within the same file that checks whether the user is logged in or not.

Example: When PHP function exists inside the same file.

Consider the following code inside HTML file:

<!DOCTYPE html> 
<html> 
  
<head> 
    <title> 
        How to display popup message  
        when logged out user try to  
        vote? 
    </title> 
</head> 
  
<body> 
    <form method="POST" action=""> 
        <p> VOTE HERE! </p> 
        <button type="submit">Vote </button> 
    </form> 
  
    <?php
        if(!isset($_SESSION[''])) { 
            echo " <script type='text/javascript'>"; 
            echo "alert('User not logged in!')"; 
            echo " </script>";  
        } 
    ?> 
</body> 
  
</html> 

Output:

Before Clicking on Vote button:
After clicking on Vote button:

Example: When PHP function exists in another file.

Consider the following code inside HTML file:

<!DOCTYPE html> 
<html> 
  
<head> 
    <title> 
        How to display popup message  
        when logged out user try to  
        vote? 
    </title> 
</head> 
  
<body> 
    <form method="POST" action="check.php"> 
        <p> VOTE HERE! </p> 
        <button type="submit">Vote </button> 
    </form> 
</body> 
  
</html> 

Consider the following code inside the check.php file:

<?php 
    if(!isset($_SESSION[''])) { 
      echo "<script type='text/javascript'>"; 
      echo "alert('User not logged in!')"; 
      echo "</script>";  
    } 
?> 