JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="container">Input
        <form class="form-inline" role="form">
            <div class="form-group">
                <input type="text" class="form-control" id="getString" placeholder="Enter some string">
            </div>
            <button type="button" class="btn btn-primary" id='nowBtn'>Now</button>
        </form>
        <br>
        <br>All Headings
        <textarea class="form-control" rows="6"></textarea>
    </div>
</body>

JavaScript

$(document).ready(function () {
    $('.btn-primary').on('click', function () {
        inputVal = $('#getString').val();
        newTextAreaVal = "<h1>" + inputVal + "</h1>";
        $('textarea').val(newTextAreaVal);
    });
    });