title: jQuery(event): watch element style
body: <p>let say have element like this</p>
  
  <pre><code>&lt;div class="watch-me" style="display: none;"&gt;Watch Me Please&lt;/div&gt;
  </code></pre>
  
  <p>as we can see the element above style is <code>display: none</code>, how can i make script to watch this element. when that element style is change to <code>display: block</code> then there is some code will be trigger.</p>
  
  <p>many thanks...</p>