JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="cbx0" value="-1" onclick="doAll(this)">All<br/>
  
  
  <input type="checkbox" class="cb" id="cbx1" value="0">Option1<br>
  
  
  
<input type="checkbox" class="cb" id="cbx2" value="1">Option2<br>

JavaScript

function doAll(obj) {
    var cb = document.getElementsByClassName("cb");
 alert(cb.val);
    for (var i = 0; i < cb.length; i++) {
        cb[i].checked = obj.checked;
        alert(cb[i].checked);
    }
}