JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="textareax"></textarea>

JavaScript

var data = "<a href=\"#\" onclick=\"javascript:document.getElementById('textareax').value += '\\r\\nTEST';\">Add</a>";

$.ajax({ url: "/echo/html/",
         data: {html: data},
         type: "POST",
         success: function(x) {
             $('body').append(x);
         }
        });