var xhr = new XMLHttpRequest();
xhr.open('GET', '/us/' + user + '?format=json');
xhr.onload = function () {
localStorage.setItem('tracker_data', this.responseText);
var xhr = new XMLHttpRequest();
xhr.open('GET', '/us/' + user + '?format=json');
xhr.onload = function () {
localStorage.setItem('tracker_data', this.responseText);