JSFiddle - React, Tailwind, and code Playground
HTML
<div class="tab-content">
<div class='tab-pane'>1</div>
<div class='tab-pane'>2</div>
</div>
<div class="tab-content">
<div class='tab-pane'>1</div>
<div class='tab-pane'>2</div>
</div>
CSS
.active {
background-color: red;
}
JavaScript
$(".tab-content").each(function() {
$(this).children(".tab-pane").first().addClass("active");
});