JSFiddle - React, Tailwind, and code Playground

HTML

<div>Please select operation:
    <br />
    <input type="radio" id="op1" name="op" value="check_username">Check Username
    <br />
    <input type="radio" id="op2" name="op" value="find_profile">Find Profile
    <br />
    <input type="radio" id="op3" name="op" value="check_credentials">Check Credentials</div>
<br />
<div id="un">Username:
    <br />
    <input type="text" />
</div>
<div id="pwd">Password:
    <br />
    <input type="text" />
</div>

JavaScript

$(document).ready(function () {
    $('#un, #pwd').hide();
    $('input[name="op"]').prop('checked', false);
    $("input[type=button]").attr("disabled", "disabled");

    $('input:radio[name=op]').change(function () {
        var op = $('input:radio[name=op]:checked').val();
        alert(op);
        switch (op) {
            case 'check_username':
                $('#un').show();
                $('#pwd').hide();
                break;
            case 'find_profile':
                $('#un').show();
                $('#pwd').hide();
                break;
            case 'check_credentials':
                $('#un, #pwd').show();
                break;
        }
    });
});