JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    Username<br />
    <input type="text" id="user_input" name="username" class="manifestSubmit"/><br />
    Password<br />
    <input type="password" id="pass_input" name="password" class="manifestSubmit"/><br />
    Confirm Password<br />
    <input type="password" id="v_pass_input" name="v_password" class="manifestSubmit"/><br />
    Email<br />
    <input type="text" id="email" name="email" class="manifestSubmit" /><br /> 
    <select class="manifestSubmit">
      <option>Please Choose</option>
      <option value="1">THIS IS CHOSENNNNN</option>
    </select>
    <input type="submit" id="register" value="Register" disabled="disabled" />
</form>
<div id="test">
</div>

JavaScript

(function() {
    $('.manifestSubmit').change(function() {

        var empty = false;
        $('.manifestSubmit').each(function() {
            if ($(this).val() == '') {
                empty = true;
            }
        });

        if (empty) {
            $('#register').attr('disabled', 'disabled');
        } else {
            $('#register').removeAttr('disabled');
        }
    });
})()