JSFiddle - React, Tailwind, and code Playground

HTML

<input name="PO_ALL" type="checkbox" id="PO_ALL" value="checkbox" onclick="CheckPowerAll()" />

<div><input name="PO_PowerWindows" type="checkbox" class="PO_PowerWindows" value="1" /> 1</div>
<div><input name="PO_PowerWindows" type="checkbox" class="PO_PowerWindows" value="2" /> 2</div>
<div><input name="PO_PowerWindows" type="checkbox" class="PO_PowerWindows" value="3" /> 3</div>
<div><input name="PO_PowerWindows" type="checkbox" class="PO_PowerWindows" value="4" /> 4</div>

JavaScript

function CheckPowerAll() {
		var elements = document.getElementsByName("PO_PowerWindows");
		var l = elements.length;
		
	    if (document.getElementById("PO_ALL").checked) {
	        for (var i = 0; i < l; i++) {
	        	elements[i].checked = true;
	        }
	    } else {
	        for (var i = 0; i < l; i++) {
	        	elements[i].checked = false;
	        }
	    }
	}