title: How can I avoid jQuery scripts being loaded multiple times?
body: <p>On my site, I load jQuery UI script using the following code:</p>
  
  <p><code>wp_enqueue_script('nf-jquery-ui','http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/jquery-ui.min.js')</code></p>
  
  <p>In my plugin I use the following code:</p>
  
  <p><code>wp_enqueue_script('wp_filebrowser-jqueryui','http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/jquery-ui.js')</code></p>
  
  <p>The result is that both these lines are added to my header - and loading a script twice is not very good.</p>
  
  <p>Yes, I know I can remove it from either my plugin or my site. But the point is that anyone can download my plugin, and they might already be loading the jQuery UI script.</p>
  
  <p>How can I avoid having a script being added twice?</p>