title: Add/remove class on click, Jquery
body: <p>What is the best way to add and remove classes, clicking a button back and forth?</p>
  
  <pre><code>    $('button.hamburger').on('click', function(){
        $(this).addClass('is-active');
      });
  
      $('button.is-active').on('click', function(){
        $('button.is-active').removeClass('is-active');
      });
  </code></pre>
  
  <p>It doesn't remove .is-active class.</p>
  
  <p>Do I need if statments to check whether the the element .hasClass()?</p>