It's not working. :'(

gistfile1.txt

var trackEvent = {
  "event": "test tracking pixel", 
  "properties": {
		"token": "SHHH!IT'S_SECRET!", 
		"time": Date.now(), 
		"campaign": "ad4game"
	}
};
 
var str = btoa(JSON.stringify(test));
 
var http_request = new XMLHttpRequest();
 
http_request.open( "GET", "http://api.mixpanel.com/track/?data="+str+"&ip=1");
http_request.onreadystatechange = function () {
	if (http_request.readyState === 4 && http_request.status === 200) {
		// Parse response
		var response = JSON.parse(http_request.responseText);
		console.log(response);
	}
};
http_request.send(null);