JSFiddle - React, Tailwind, and code Playground

HTML

<table border=1 width=200px>
    <tr class="a">
        <td>a</td>
    </tr>
    <tr class="b">
        <td>b</td>
    </tr>
    <tr class="b">
        <td>b</td>
    </tr>
    <tr class="c">
        <td>c</td>
    </tr>
    <tr class="c">
        <td>c</td>
    </tr>
</table>

JavaScript

$(function(){
    $("tr.b:first").before("<tr><td>css selector</td></tr>");
    $("table tr.b").first().before("<tr><td>jquery only</td></tr>");
});