PHP if statement - can I use it like this?
<pre><code>if(!isset($_GET['set']) &amp;&amp; (($_GET['set'] != 'on') || ($_GET['set'] != 'off'))){
    header('Location: http://google.com');
    exit;
}
</code></pre>

<p>What I want to check is if set has not set and value is not on or off. Is this right or is there any other way?</p>
