JSFiddle - React, Tailwind, and code Playground

HTML

<select id='sel' size='1'>
    <option>&#60;&#62;&#60;&#47;&#62;</option>
    <option>&#60;p&#62;&#60;&#47;p&#62;</option>
    <option>&#60;div&#62;&#60;&#47;p&#62;</option>
    <option>&#60;a&#62;&#60;&#47;a&#62;</option>
</select><br/><br/>
<textarea id='txtarea'></textarea>

CSS

textarea{width:100%;height:200px;}

JavaScript

$(document).ready(function() {
    $('select').change(function() {
        var currentVal = $('textarea').val();
        $('textarea').val(currentVal + $(this).val()); 
    });
});