JSFiddle - React, Tailwind, and code Playground
HTML
<h1>Hello you there</h1>
<h1>Hi u there</h1>
<h1>Can we go there</h1>
CSS
.myColor{
color : red
}
JavaScript
var text = $('h1').text().split(' ');
var lstWord = text.pop();
$("h1:eq(0)").html(function(i, old) {
return old.replace(lstWord, '<span class="myColor">'+lstWord+'</span>');
});