JSFiddle - React, Tailwind, and code Playground

HTML

<center>
<table cellspacing="1" cellpadding="1" border="3" rules="all">
<tbody>
<tr>
    <td align="center">
        <table>
            <tbody>
            <tr>
                <td></td>
            </tr>
            </tbody>
        </table>
    </td>
    <td nowrap="1" align="center" colspan="12">
        <table>
            <tbody>
            <tr>
                <td nowrap="1" align="center"><font size="2" face="Arial" color="#000000">
                    Caption 1
                </font></td>
            </tr>
            </tbody>
        </table>
    </td>
    <td nowrap="1" align="center" colspan="12">
        <table>
            <tbody>
            <tr>
                <td nowrap="1" align="center"><font size="2" face="Arial">
                    Caption 2
                </font></td>
            </tr>
            </tbody>
        </table>
    </td>
    <td nowrap="1" align="center" colspan="12">
        <table>
            <tbody>
            <tr>
                <td nowrap="1" align="center"><font size="2" face="Arial">
                    Caption 3
                </font></td>
            </tr>
            </tbody>
        </table>
    </td>
    <td nowrap="1" align="center" colspan="12">
        <table>
            <tbody>
            <tr>
                <td nowrap="1" align="center"><font size="2" face="Arial">
                    Caption 4
                </font></td>
            </tr>
            </tbody>
        </table>
    </td>
    <td nowrap="1" align="center" colspan="12">
        <table>
            <tbody>
            <tr>
                <td nowrap="1" align="center"><font size="2" face="Arial">
                    Caption 5
                </font></td>
            </tr>
            </tbody>
        </table>
    </td>
</tr>
<tr>
    <td nowrap="1" align="center" rowspan="2">
        <table>
            <tbody>
            <tr>
                <td nowrap="1" align="center"><font size="2" face="Arial">
                    <b>1</b>
       ...

JavaScript

// ### debug ###
$('table').on('click', 'td[rowspan]', function () {
    var $this = $(this),
        num = $this.siblings(':first-child').text().trim(),
        pos = $this.index() + 1,
        name = $this.parent().siblings().first().children(':nth-child(' + pos + ')').text().trim();
    alert(num + ':' + name);
});
// ### /debug ###

$(document).ready(function () {
        $("table").find("tr:has(td[rowspan])").each(function (index, obj) {
            $(this).find("td").each(function (index, obj) {
                // debug
                 $(this).css('border', 'solid 1px red');
                
    var $this = $(this),
        num = $this.siblings(':first-child').text().trim(),
        pos = $this.index() + 1,
        name = $this.parent().siblings().first().children(':nth-child(' + pos + ')').text().trim();
    
                if ($this.attr("rowspan") && $this.attr("colspan")) {
                    // debug
                    console.log((num + ':' + name));
                }
                // ...
            });
        });
});