ajax.js

var ajax = {
  x: [],

  abortAll: function() {
    var i;
    for (i in ajax.x) {
      if (Object.prototype.hasOwnProperty.call(ajax.x, i)) {
        ajax.x[i].abort();
      }
    }
  },

  xhr: function() {
    var a;
    for (a = 0; a < 4; a = a + 1) {
      try {
        return a ? new ActiveXObject(['', 'Msxml2', 'Msxml3', 'Microsoft'][a] + '.XMLHTTP') : new XMLHttpRequest();
      } catch (e) {}
    }
  },

  sendRequest: function(verb, url, data, success, error) {

    data = data || null;
    var xhttp = new ajax.xhr(),
      serialize = '',
      i;

    if (typeof data === 'object') {

      for (i in data) {
        if (Object.prototype.hasOwnProperty.call(data, i)) {
          serialize += '&' + i + '=' + data[i];
        }
      }
      data = serialize.substring(1);
    }

    xhttp.onreadystatechange = function() {

      if (xhttp.readyState === 4) {
        var i;
        for (i in ajax.x) {
          if (ajax.x[i] === xhttp) {
            ajax.x.splice(i, 1);
            break;
          }
        }

        if (xhttp.status === 200) {
          if (typeof success === 'function') {
            success(xhttp.responseText);
          }
        } else {
          if (typeof error === 'function') {
            error(xhttp);
          }
        }
      }
    };

    xhttp.open(verb.toString().toUpperCase(), url, true);
    xhttp.send(data);

    ajax.x.push(xhttp);

  },

  GET: function(url, success, error) {
    ajax.sendRequest('GET', url, null, success, error);
  },

  POST: function(options, success, error) {
    ajax.sendRequest('POST', options.url || options, options.data || null, success, error);
  }

};