Why does this code returns "true"? : <p>I have some weird situation with following code:</p>

<pre><code>$string = '///';
var_dump(!stripos($string, '//')); 
</code></pre>

<p>This code section returns <code>true</code>. Now take a look at next code section:</p>

<pre><code>$string = 'a//';
var_dump(!stripos($string, '//'));
</code></pre>

<p>This code section returns <code>false</code>.
At my opinion fisrt example should return <code>false</code> too, but it isn't. What am I doing wrong?</p>
