JSFiddle - React, Tailwind, and code Playground

HTML

<table id="first" width="600" border="1" cellspacing="0" cellpadding="0">
    <tr>
        <td>hdng 1</td>
        <td>hdng 2</td>
        <td>hdng 3</td>
        <td>hdng 4</td>
        <td>hdng 5</td>
                <td>hdng 6</td>
    </tr>
</table>
<table width="600" border="1" cellspacing="0" cellpadding="0">
    <tr>
        <td>content content content</td>
        <td>con</td>
        
        <td>content content content</td>
        <td>content content content</td>
        <td>content content content</td>
        <td>content content content</td>
    </tr>
</table>

CSS

table { margin-bottom: 5px; }

JavaScript

var num = $("table#first tr:first-child > td").length;
    var width = (100 / num) + "%";
    
    $("td").css("width", width);