JSFiddle - React, Tailwind, and code Playground

HTML

<table border="1">
    <thead>
    <tr>
        <th>HEAD1</th>
        <th>HEAD2</th>
        <th>HEAD3</th>
    </tr>
    </thead>
    <tr>
        <td class="hiddenField">row1 col1</td>
        <td>x</td>    
        <td><button class="seeHidden">btn1</button></td>
    </tr>
        <tr>
        <td class="hiddenField">row2 col1</td>
        <td>y</td>
        <td><button class="seeHidden">btn2</button></td>
    </tr>
</table>

CSS

th:nth-child(1), td:nth-child(1){
    display: none;
}

JavaScript

$(".seeHidden").click(function(){
    var hiddenField = $(this).parent()
                             .siblings("td.hiddenField")
                             .html();
    alert(hiddenField);
});