JSFiddle - React, Tailwind, and code Playground

HTML

<table>
<thead><tr><th>col 1 <span class="hideme">content</span></th><th>col 2<span class="hideme">content</span></th><th>col 3</th></tr></thead>
<tbody>
  <tr><td>col 1 content</td><td>col 2 content</td><td>col 3 content</td></tr>
</tbody>
</table>

CSS

/** .hideme{display:none} **/
.showme{display:block}
span{display:block; height:200px; width:200px; background-color:#ff0}

JavaScript

$("th").click(function(){
 // $(this).(".hideme").addClass("showme");
// $("this").find("span").addClass("showme");
// $(this).find( "span" ).css( "display", "block" );
$(this).find( "span" ).toggle();
console.log('moo');
});