JSFiddle - React, Tailwind, and code Playground

HTML

number of passed hours:
<input type="number" id="hrs"> Overall average:
<input type="number" id="avg">
<div id="d1">

</div>
<button id="add">
  Add Course
</button>

JavaScript

var i = 1;

$("#add").click(function() {
    $("<input id='subState" + i + "' class='repSub' type='checkbox'>").appendTo("#d1").promise().done(function(){
        hour = Number($("#hrs").val());
  			avg = Number($("#avg").val());
  			if (hour === 0 && avg === 0) {
   				 $(".repSub").prop("disabled", true);
  			} 
        else {
        $(".repSub").prop("disabled", false);
        }
    });
  i++;
});