JSFiddle - React, Tailwind, and code Playground

HTML

Fill this before you continue:
<input id="a" />
<br>
<br>
Fill this after the previous input
<input id="b" disabled />

JavaScript

$('#a').bind('input propertychange', function() {
    var value = $('#a').val();
    if (value == "")
        $('#b').attr('disabled', 'disabled');
    else
        $('#b').removeAttr('disabled');

});