Question

I am trying to display a div only if the user is logged in, therefore only if $_SESSION['MM_Username'] exists and is equal to something so to achieve this I came up with the following code. The session variables are set and I know they exist however when I log out I still see the div:

<ul id="example-1" class="sticklr" style="list-style:none;display:<?php if ($_SESSION['MM_Username']=='' & $_SESSION['MM_Username']==NULL){echo('none');}?>">

How can I debug this to see whats the problem, or if someone knows a better way to display a div only if user is logged in please let me know .

Answer 1

To check if a variable is set in PHP you can use the isset() function:

<?php

//this checks to see if the variable isset and not null, if it is not set or is null then echo 'none';
if (!isset($_SESSION['MM_Username']) || empty($_SESSION['MM_Username'])){
    echo 'none';
}

?>

empty() checks if there is a value associated with the variable: http://php.net/empty

If a variable has been unset with unset(), it will no longer be set.
isset() will return FALSE if testing a variable that has been set to
NULL. Also note that a NULL byte (“\0”) is not equivalent to the PHP
NULL constant.

Source: http://php.net/isset

One cool thing about isset() is that it won’t throw an error or warning message when you ask if a variable is set that is not.