JSFiddle - React, Tailwind, and code Playground

HTML

<div id="paymentchoice">Creditcard
    <input type="radio" name="paymentProcessor" id="creditcard" value="creditcard">Paypal</input>
        <input type="radio" name="paymentProcessor" id="paypal" value="paypal" checked/>
</div>
<div id="card" class="hidden">
    <input type="text" name="cardname">
    <input type="text" name="cardnum">
    <input type="text" name="cardcode">
    <select name="month">
        <option value="01">01</option>
        <option value="02">02</option>
        <option value="03">03</option>
        <option value="04">04</option>
    </select>
    <select name="year">
        <option value="volvo">Volvo</option>
        <option value="saab">Saab</option>
        <option value="fiat">Fiat</option>
        <option value="audi">Audi</option>
    </select>
</div>
<input type="submit" value="Submit">

CSS

.hidden {
    display:none;
}

JavaScript

// IF JAVASCRIPT ENABLED...

// select card option by default
$('input:radio[name="creditcard"]').prop("checked", true);
// unhide payment options
$('#paymentchoice').removeClass('hidden');
// unhide card options
$('input[name="paymentProcessor"]').change(function(){
if ($('#creditcard').is(':checked'))
    $('#card').removeClass('hidden');
else
    $('#card').addClass('hidden');
});