JSFiddle - React, Tailwind, and code Playground

HTML

<div class="hashtag">#one</div>
        <div class="hashtag">#two</div>
        <form accept-charset="UTF-8" action="/home/index" method="post">
            <textarea id="text-box"></textarea>
            <input type="submit" value ="ok" id="go" />
        </form>

JavaScript

$(document).ready(function(){

  $(".hashtag").click(function(){
    var txt = $.trim($(this).text());
    var box = $("#text-box");
    box.val(box.val() + txt);
  });
});