javascript injection on uiwebview to catch ajax request

(function(XHR) {
  var send = XHR.prototype.send;
  XHR.prototype.send = function(data) {
    var self = this;

    function onReadyStateChange() {
      if(self.readyState == 4 ) {
        windows.location = 'ajaxHandler://' + self.url;
      }
    }

    this.addEventListener("readystatechange", onReadyStateChange, false);
    send.call(this, data);
  }
})(XMLHttpRequest);