title: How can I know if google spiders or another spiders visit my page?
body: <p>How can I know if google spiders or another spiders visit my page ?</p>
  
  <pre><code>&lt;?php
  
  if ("this is a spider") {
  header('Location: index.php');
  exit;
  }
  
  ?&gt;
  </code></pre>