AJAX

var Ajax = {
  get: function (url, fn) {

    var xhr = new XMLHttpRequest();
    xhr.open('GET', url, true);
    xhr.onreadystatechange = function () {

      if (xhr.readyState == 4 && xhr.status == 200 || xhr.status == 304) {

         fn.call(this, xhr.responseText);
      }
    };
    xhr.send();
  },

  post: function (url, data, fn) {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", url, true);

    xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    xhr.onreadystatechange = function () {
      if (xhr.readyState == 4 && (xhr.status == 200 || xhr.status == 304)) {
        fn.call(this, xhr.responseText);
      }
    };
    xhr.send(data);
  }
}