title: jQuery count div that has a display:none attribute
body: <p>I want to count the div that has a class name "items" and has an attribute "style=display:none".</p>
  
  <pre><code>&lt;div id="skills"&gt;
  &lt;div class="items" style="display:none"&gt;1&lt;/div&gt;
  &lt;div class="items"&gt;2&lt;/div&gt;
  &lt;div class="items"&gt;3&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;4&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;5&lt;/div&gt;&lt;/div&gt;
  </code></pre>
  
  <p>the output should be '3'.</p>
  
  <p>===========================================================</p>
  
  <p>addition to the problem:</p>
  
  <pre><code>&lt;div id="skills1"&gt;
  &lt;div class="items" style="display:none"&gt;1&lt;/div&gt;
  &lt;div class="items"&gt;2&lt;/div&gt;
  &lt;div class="items"&gt;3&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;4&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;5&lt;/div&gt;&lt;/div&gt;
  
  &lt;div id="skills2"&gt;
  &lt;div class="items" style="display:none"&gt;1&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;2&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;3&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;4&lt;/div&gt;
  &lt;div class="items" style="display:none"&gt;5&lt;/div&gt;&lt;/div&gt;
  </code></pre>
  
  <p>the output should be '3' &amp; '5'.</p>