JSFiddle - React, Tailwind, and code Playground

HTML

<div class="itemRelated">
    <ul>
        <li class="even">Hi There</li>
        <li class="odd">Whats'up</li>
        <li class="even">BugsBunny</li>

CSS

.cf {
    color:red;
}

JavaScript

var list;
list = document.querySelectorAll("li.even, li.odd");
for (var i = 0; i < list.length; ++i) {
    list[i].classList.add('cf');
}