JSFiddle - React, Tailwind, and code Playground

HTML

<div class="message">Lorem Ipsum</div>
<div class="message">Dolor Sit</div>

CSS

span.em { color:red; }

JavaScript

$('div.message').each(function() {
   var html = $(this).html();
   var word = html .substr(0, html.indexOf(" "));
   var rest = html .substr(html.indexOf(" "));
   $(this).html(rest).prepend($("<span/>").html(word).addClass("em"));
});