JSFiddle - React, Tailwind, and code Playground

HTML

<h3 class="foo">hello world! hello world! hello world</h3>
<div class="foo">hello world! hello world hello world!</div><span class="foo">hello world! hello world</span>

CSS

.foo::selection {
    color:#ff0099;
}

.bar::selection {
    color: red;   
}

JavaScript

$(document).ready(function(){
    $(".foo").removeClass("foo").addClass("bar");
});