title: javascript hide/show items in dropdown list
body: <p>I started studying javascripting and was wondering if anyone know how to hide values in dropdown list for html?</p>
  
  <p>For example: a dropdwon list with values</p>
  
  <pre><code>Select One   
  Item1   
  Item2    
  Item3  
  Item4  
  Item5
  </code></pre>
  
  <p>I wanna hide the Item 4 and 5, like this and show it when "Show... " is clicked.</p>
  
  <pre><code>Select One  
  Item1  
  Item2  
  Item3  
  Show 2 more items (Item 4 and 5 hidden)
  </code></pre>
  
  <p>Is that possible? Below is a piece of code i already started.</p>
  
  <pre><code>var css = select;
  var markers = cluster.getMarkers();
  var markersLength = markers.length;
  
  var nextOption = new Option("Select One");
  css.add(nextOption, 0);
  
  for(var i = 0; i &lt; markersLength; i++) {
  
      nextOption = new Option(markers[i].title);
      try {
          css.add(nextOption, -1);
      } catch (e) {
          css.add(nextOption, null);
      }
  }
  </code></pre>