JSFiddle - React, Tailwind, and code Playground

HTML

<input id="mfrmAdd" type="button" value="add" />
<table style="background-color:blue;">
    <tr>
        <td>column1</td>
        <td>column2</td>
    </tr>
    <tr id="startPoint"><td colspan="2"></td></tr>
</table>

JavaScript

$(document).ready(function () {
        $("#mfrmAdd").on("click", function () {
                var _tr;
                _tr = "<tr id='foo1'>" +
                "<td>col1</td>" +
                "<td>col2</td>" +
                "</tr>";
                $(_tr).hide().insertAfter("#startPoint").fadeIn('slow');
        });
    });