JSFiddle - React, Tailwind, and code Playground

HTML

<div id="links">
    <a href="http://fiddle.jshell.net/#foo">Inbound Link</a>
    <a href="http://stackoverflow.com">Outbout Link</a>
</div>

JavaScript

var link_container = document.getElementById('links');

link_container.addEventListener('click', function(e){ 
    if(e.target.nodeName === "A"){
        var href = e.target.getAttribute('href'),
            selfhost = window.location.hostname;
        if(href.indexOf(selfhost) !== -1){
            alert('Inbound link clicked');
        } else {
            alert('Outbound link clicked');
        }
    }
}, false);