Foundation Accordion

HTML

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/foundation/5.5.3/css/foundation.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/foundation/5.5.3/js/foundation.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/foundation/5.5.3/js/foundation/foundation.accordion.min.js"></script>
<ul class="accordion" data-accordion="myAccordionGroup">
  <li class="accordion-navigation step-1">
    <a href="#panel1c">Step 1</a>
    <div id="panel1c" class="content">
      Panel 1. Lorem ipsum dolor
    </div>
  </li>
  <li class="accordion-navigation step-2">
    <a href="#panel2c">Step 2</a>
    <div id="panel2c" class="content">
      Panel 2. Lorem ipsum dolor
    </div>
  </li>
  <li class="accordion-navigation step-3">
    <a href="#panel3c">Step 3</a>
    <div id="panel3c" class="content">
      Panel 3. 
      <br>
      <button type='button' id='disable-steps'>Disable steps 1 & 2</button> 
    </div>
  </li>
</ul>

JavaScript

$(document).foundation('accordion');

$('body').on('click', '#disable-steps', function(){
  $('.step-1,.step-2').addClass('disabled');
})

$('.accordion').on('toggled', function (event, accordion) {
  if(accordion.parents('li').hasClass('disabled'))
});