Checkbox does not work when clicking on it

I change this code: Demo1[ https://ift.tt/3fmzNs3 ]

<li class="nav-item">
   <span class="nav-switch" href="#">
     <span class="language" id="eg">EG</span>
       <label class="switch">
           <input type="checkbox">
           <span class="slider round"></span>
      </label>
    <span  class="language" id="ar">AR</span>
  </span>
</li>

To this code: Demo2[ https://ift.tt/3yetcsl ]

<li class="nav-item">
   <span class="nav-switch" href="#">
     <span class="language" id="eg">EG</span>
       <a class="switch">
           <input type="checkbox">
           <span class="slider round"></span>
       </a>
    <span  class="language" id="ar">AR</span>
  </span>
</li>

To be able to take action when changing from one language to another using the checkbox but after making that change, the color of the checkbox does not change as in Demo1, I need to take action because I use PHP/Laravel

via Chebli Mohamed