JSFiddle - React, Tailwind, and code Playground

HTML

<table>
<thead>
    <tr>
        <th>HEAD</th>
        <th>HEAD</th>
        <th>HEAD</th>        
    </tr></thead>
<tbody>
    <tr>
        <td>BODY</td>        <td>BODY</td>        <td>BODY</td>
    </tr>    <tr>
        <td>BODY</td>        <td>BODY</td>        <td>BODY</td>
    </tr>    <tr>
        <td>BODY</td>        <td>BODY</td>        <td>BODY</td>
    </tr>    <tr>
        <td>BODY</td>        <td>BODY</td>        <td>BODY</td>
    </tr>
</tbody>
</table>

CSS

th
{
 background: green;   
}
td
{
 background: blue;   
}

JavaScript

$("th").outerWidth(true);