google analytics tag outbound links

ga_out_tag.js

document.addEventListener('DOMContentLoaded', ()=>{
        if ("ga" in window) {
        tracker = ga.getAll()[0];
        var a = document.getElementsByTagName("a");
        for(i = 0; i < a.length; i++) {
            if (a[i].href.indexOf(location.host) == -1 && a[i].href[0] != "#") {
                let url = a[i].href;
                a[i].onclick = function(e){
                    tracker.send('event', 'outbound', 'click', url.replace("https:\/\/", ""), {
                     'transport': 'beacon',
                     'hitCallback': function(){window.open(url);}
                    });
                    e.preventDefault();
                    return false;
                }
            }
        }
    }
})