JSFiddle - React, Tailwind, and code Playground

HTML

<textarea></textarea>

JavaScript

$('textarea').on('paste keyup keydown', function (event) {
  var element = this;
  setTimeout(function () {
   if($(element).val().length > 500)
     {
     if(event.type=="paste"){
    $(element).val($(element).val().substr(0,500))    
         }else{
    $(element).val($(element).val().slice(0,-1));
         }
     alert("excceded more then 500 characters");
   }else{
    return true;
   }
  }, 100);
});