JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li><a href="#" class="enlace">Inicio</a></li>
    <li><a href="#" class="enlace">Otro</a></li>
</ul>

CSS

a.enlace{
    color:blue;
}
a.enlace.activo{
    color:red;
}

JavaScript

function AddEvent(html_element, event_name, event_function) 
{       
   if(html_element.attachEvent)
      html_element.attachEvent("on" + event_name, function() {event_function.call(html_element);}); 
   else if(html_element.addEventListener) 
      html_element.addEventListener(event_name, event_function, false);     
} 
var elements = document.getElementsByClassName('enlace'); 
for(var i = 0, j = elements.length; i < j; i++){
	AddEvent(elements[i], 'click', function(){
		var elementos = document.getElementsByClassName('enlace activo'); 
        for (var i = elementos.length - 1; i >= 0; i--)
        {
          elementos[i].className = "enlace";
        }
        this.className = "enlace activo";
    });
};