JSFiddle - React, Tailwind, and code Playground

HTML

<table id="element1" class="eshot_dd_elementDraggableRestricted ui-draggable" width="100%" border="0" cellspacing="0" cellpadding="0" style="border-collapse:collapse; border-spacing:0;" eshot_dd_eshotelementtype="elementDivider">
<tbody>
<tr>
<td style="border-bottom: 30px solid rgb(199, 72, 72); line-height: 1px; font-size: 1px;">
<span></span>
</td>
</tr>
    <tr>
        <td id="result"></td>
    </tr>
</tbody>
</table>

CSS

#element1 td{
    display: block;
}

JavaScript

$('#result').html('The border-bottom-width is: ' + $('#element1').find('td').css('border-bottom-width'));