title: How can I hide and show rows in my table using jQuery?
body: <p>I have a table where my rows have classes:</p>
  
  <pre><code>&lt;table id="abc"&gt;
  &lt;tr class="level-0"&gt;
  &lt;tr class="level-1"&gt;
  &lt;tr class="level-2"&gt;
  &lt;/table&gt; 
  </code></pre>
  
  <p>I need to create two buttons. </p>
  
  <ul>
  <li>[Hide level 1 and 2] - when clicks this hides or shows all the
  level-2 rows.</li>
  <li>[Hide level 2] - when clicks this hides or shows the level-1 and level-2 rows.</li>
  </ul>
  
  <p>Can someone tell me how I can implement this with jQuery?</p>