JSFiddle - React, Tailwind, and code Playground

HTML

<form action=""  method="post" onSubmit="return checkTheBox() " name="checkboxform">
     <input type='checkbox' name='checkid[]' value=''/>
     <input type='checkbox' name='checkid[]' value=''/>
     <input type='checkbox' name='checkid[]' value=''/>
     <input type='checkbox' name='checkid[]' value=''/>
</form>

<td><a href='javascript:void(0);' onClick="javascript:checkAll('checkboxform', true);"><b>Check All</b></a> | 
     <a href='javascript:void(0);' onClick="javascript:checkAll('checkboxform', false);"><b>UnCheck All</b></a></td>

JavaScript

function checkAll(formname, checktoggle)
   {
   var checkboxes = new Array();
   checkboxes = document[formname].getElementsByTagName('input');
  for (var i = 0; i < checkboxes.length; i++) {
      if (checkboxes[i].type === 'checkbox') {
           checkboxes[i].checked = checktoggle;
          }
      }
  }