ajax.js

/*globals ActiveXObject*/

// Cross browser Ajax implementation based on
// http://toddmotto.com/writing-a-standalone-ajax-xhr-javascript-micro-library/
// https://gist.github.com/Xeoncross/7663273

var encodeParams = function(data, bustCache) {
  var key,
    params = [];
  for (key in data) {
    if (data.hasOwnProperty(key)) {
      params.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
    }
  }
  if (bustCache) {
    params.push('_t=' + Date.now());
  }
  return params.join('&');
};

var parse = function(req) {
  var result;
  try {
    result = JSON.parse(req.responseText);
  } catch (e) {
    result = req.responseText;
  }
  return [result, req];
};

var xhr = function(type, url, data) {
  var methods = {
    success: function() {},
    error: function() {}
  };
  var XHR = window.XMLHttpRequest || ActiveXObject;
  var request = new XHR('MSXML2.XMLHTTP.3.0');
  request.open(type, url, true);
  if (type === 'POST') {
    xhr.request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
  }
  if (data) {
    data = encodeParams(data);
  }
  request.onreadystatechange = function() {
    if (request.readyState === 4) {
      if (request.status === 200) {
        methods.success.apply(methods, parse(request));
      } else {
        methods.error.apply(methods, parse(request));
      }
    }
  };
  request.send(data);
  return {
    success: function(callback) {
      methods.success = callback;
      return methods;
    },
    error: function(callback) {
      methods.error = callback;
      return methods;
    }
  };
};