title: Expandable Tree Menu List
body: <p>What I want to achieve is the following:</p>
  
  <p>I want to have a tree-view list that will appear on the left side of the page, when an Item is expanded, it's items are loaded from a database (I can do this part), so basically it will go like this:</p>
  
  <pre><code>+Category1
  +Category2
  +Category3
  +Category4
  </code></pre>
  
  <p>When the user clicks on <code>+</code>, it will show the below till the data is grabbed from DB and added to the page:</p>
  
  <pre><code>+Category1
  -Category2
      loading ...
  +Category3
  +Category4
  </code></pre>
  
  <p>After the data is loaded, each sub-category WILL have sub-sub-category.</p>
  
  <pre><code>+Category1
  -Category2
      +Sub-Cat1
      +Sub-Cat2
      +Sub-Cat3
      +Sub-Cat4
  +Category3
  +Category4
  </code></pre>
  
  <p>How can I achieve this?</p>
  
  <p>NOTE: I want to know how to put (<code>*</code> or <code>&gt;</code> or any other symbol for the list, I believe this is CSS but I don't work with design at all!!) </p>
  
  <p>Your help is really appreciated.</p>