Hi everyone, 

I have set up a checkbox that will enable itself when a text area is fully scrolled, and it works fine for PC but I couldn't get it to work 100% of the time on mobile. Sometimes I need to scroll down a couple more times, sometimes I need to click on the text area first then scroll down, I don't really know what causes this issue.  Here's the javascript I used if anyone can help me take a look at it, thank you.

function checkScrollEnd(cls){
  var textarea = document.querySelector('.' + cls + ' > span > span > textarea:first-of-type');
  if(textarea) {
    textarea.addEventListener('scroll',setFlg.bind(this));
  }
  textarea.readOnly = "true"
  function setFlg() {
      var scrollHeight = textarea.scrollHeight;
      var scrollTop = textarea.scrollTop;
      var clientHeight = textarea.clientHeight;
 
      if (scrollHeight - scrollTop < clientHeight + 2) {
       if (cls == "ScrollCheck") {
         var elementInd = document.querySelector('input[type="checkbox"][name="checkboxenable"]');
         if (elementInd) {
           elementInd.removeAttribute('disabled');
 

      }
       }       
      }
    }