JSFiddle - React, Tailwind, and code Playground

HTML

<p class="greeting">
    Hello, my name is Kevin. what's yours?
    <br>
    My name is Kevin, too. 
</p>

CSS

.highlight { background-color: yellow; }

JavaScript

var text = 'My namE iS';

$( 'p.greeting' ).html( function ( i, html ) {
    var regexp, replacement;
        
    regexp = RegExp( '(' + text + ')', 'gi' );
    replacement = '<span class="highlight">$1</span>';
    
    return html.replace( regexp, replacement );
});