track cloudflare's edge location by using GA event

cloudflare.html

<script>
(function(){
var request = new XMLHttpRequest();
request.open('GET', '/cdn-cgi/trace', true);
request.onload = function() {
  if (request.status != 200) return;
  var match = request.responseText.match(/(colo|loc)=(\w+)/g),
  colo = match[0].split('=')[1], loc = match[1].split('=')[1];
  ga('send', 'event', 'cloudflare', loc, colo);
};
request.send();
})();
</script>