JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr>
        <td>1</td>
        <td>2</td>
        <td>3</td>
        <td >3</td>
        <td>4</td>
        <td>1</td>
        <td>2</td>
        <td>3</td>
        <td >3</td>
        <td>4</td>
    <tr>
    <tr>
        <td>1</td>
        <td>2</td>
        <td>3</td>
        <td >3</td>
        <td>4</td>
        <td>1</td>
        <td>2</td>
        <td>3</td>
        <td >3</td>
        <td>4</td>
    <tr>
</table>

JavaScript

$(function() {
    var colCount = 0;
    $('tr:nth-child(1) td').each(function () {
        if ($(this).attr('colspan')) {
            colCount += +$(this).attr('colspan');
        } else {
            colCount++;
        }
    });
    alert(colCount);
});