JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="main-menu">
    <li><a>What</a></li>
    <li><a>What</a></li>
    <li><a>What</a></li>
    <li><a>What</a></li>
</ul>

JavaScript

var lis = document.getElementById('main-menu').children;

Array.prototype.forEach.call(lis, function(li) {
    var anchors = li.getElementsByTagName('a');
    Array.prototype.forEach.call(anchors, function(a) {
        a.style.color = 'green';
    });
});


var anchors = document.querySelectorAll('ul#main-menu li a');

for(var i = 0; i < anchors.length; i ++) {
    anchors[i].style.color = 'red';
}