title: jQuery -> check the visibility of an element
body: <p>I have a div element which will be shown/hidden in many places.
  Is it possible if I do a </p>
  
  <pre><code>$("#divtobetracked").hide();
  </code></pre>
  
  <p>or a </p>
  
  <pre><code>$("#divtobetracked").show();
  </code></pre>
  
  <p>that another action is fired?
  Because if .hide() of the element, a button should also be hidden, and if the element wil be shown, a button should also be displayed.</p>
  
  <p>So, I think I can write a function which toggle and do the things I want and I call the function if I want to show/hide the element.</p>
  
  <p>But, is there another possibility, sth. like a .live() event?</p>
  
  <p>Best Regards.</p>