title: PHP check if url parameter exists
body: <p>I have a URL which i pass parameters into</p>
  
  <blockquote>
    <p>example/success.php?id=link1</p>
  </blockquote>
  
  <p>I use php to grab it</p>
  
  <pre><code>$slide = ($_GET["id"]);
  </code></pre>
  
  <p>then an if statement to display content based on parameter</p>
  
  <pre><code>&lt;?php  if($slide == 'link1') { ?&gt;
     //content
   } ?&gt;
  </code></pre>
  
  <p>Just need to know in PHP how to say, if the url param exists grab it and do the if function, if it doesn't exist do nothing.</p>
  
  <p>Thanks Guys</p>