JSFiddle - React, Tailwind, and code Playground

HTML

<a id="link1">Link1</a>
<br>
<a id="link2">Link2</a>

JavaScript

function flash() {
    var links = document.getElementsByTagName('a');
    for (var i = 0; i < links.length; i++) {
      links[i].style.color = (links[i].style.color=='black') ? 'white':'black';
    }
}
setInterval(flash, 1000);