JSFiddle - React, Tailwind, and code Playground

HTML

<div id="gvPerformanceResult">

<input type="checkbox" id="check1" data-count="0" /><label>Option1</label>
<input type="checkbox" id="check2" data-count="0" /><label>Option2</label>
<input type="checkbox" id="check3" data-count="0" /><label>Option3</label>
<input type="checkbox" id="check4" data-count="0" /><label>Option4</label>
<input type="checkbox" id="check5" data-count="0" /><label>Option5</label>
</div>

<button type="button" id="countr">
click
</button>
<div id="output"></div>
<p id="demo"></p>

JavaScript

//$(':checkbox').click(function () {
   // var $this = $(this);
  //  if (typeof ($this.data("count")) == 'undefined') {
    //    $this.data("count", 0);
  //  };
  //  if ($(':checkbox').attr('checked', false)) {
      //  $this.data("count", $this.data("count") + 1)
        //alert($this.data("count"));
//    }
   
    
 //   $("#output").html("");
  
    //$(":checkbox").each(function(){
       // $("#output").append(this.id + " clicks = " + $(this).data("count") + "<br />")
        
     $('#countr').click(function () {
          var check = $('input[type="checkbox"]:checked').length;
          alert(check);
   
    document.getElementById("demo").innerHTML = 5 + 6; 
   
   return false;
 
   
  //  })
  //  })
    
});


//$('#myCheckbox').attr('checked', true); // Checks it
//$('#myCheckbox').attr('checked', false); // Unchecks it