JSFiddle - React, Tailwind, and code Playground

HTML

<div class="comment"><p>Primer comentario</p>
    <span class="reply">Reply</span>
</div>
<div class="comment"><p>Segundo comentario</p>
    <span class="reply">Reply</span>
</div>
<div class="comment"><p>Tercer comentario</p>
    <span class="reply">Reply</span>
</div>
<div class="comment"><p>Cuarto comentario</p>
    <span class="reply">Reply</span>
</div>
<textarea id="new_comment" placeholder="comments"></textarea>

CSS

body{
    text-align: center;
    font: normal 100% "Tahoma", arial, sans-serif;
}
.comment, textarea{
    border: 1px solid #999;
    margin: 0 auto;
    text-align: left;
    width: 200px;
}
.comment {
    border-bottom: none;
}
span.reply{
    border-top: 1px solid #ccc;
    display: block;
    font: lighter .6em "Tahoma", arial, sans-serif;
    color: #77E1FF;
    cursor: pointer;
}

JavaScript

$('.reply').click(function(){
     $text = $(this).parent('.comment').children('p').html();
     $('#new_comment').val($text);

});