title: $_GET and WordPress
body: <p>I want to add a custom php file to a WordPress to do a simple action.</p>
  
  <p>So far I have in my theme <code>index.php</code> file:</p>
  
  <pre><code>&lt;a href="myfile.php?size=md"&gt;link&lt;/a&gt;
  </code></pre>
  
  <p>and the php is</p>
  
  <pre><code>&lt;?php echo "hello world"; ?&gt;
  
  &lt;?php echo $_GET["size"]; ?&gt;
  
  &lt;?php echo "hello world"; ?&gt;
  </code></pre>
  
  <p>The link, once clicked, displays:</p>
  
  <pre><code>hello world
  </code></pre>
  
  <p>Is WordPress taking over the <code>$_GET</code> function and I need to do some tricks to use it? What am I doing wrong?</p>
  
  <p><strong>Edit</strong>: </p>
  
  <pre><code>&lt;?echo "hello world";?&gt;
  &lt;? 
    if (array_key_exists('size', $_GET))
      echo $_GET['size'];
  ?&gt;
  &lt;?echo "end";?&gt;
  </code></pre>
  
  <p>Ouputs :</p>
  
  <pre><code>hello world
  </code></pre>