JSFiddle - React, Tailwind, and code Playground

HTML

<p id="events"></p>
<div id="cont">
    <input type="text" id="input1"/>
    <input type="text" id="input2"/>
</div>

JavaScript

(function(){
    $('#cont').on('keyup', 'input', function (event) {
            var input = this;
          if (input.value.length == 4) {
                $('#input2').focus();
            }
        });
              
               $('#cont').on('focusin', 'input', function () {
                   $('#events').append('focusin of '+this.id+' <br>');
            });

           $('#cont').on('focusout', 'input', function () {
                $('#events').append('focusout of '+this.id+' <br>');
            });
    
          })();