scrape2.rb

params = {
  cmd: 'Page.addScriptToEvaluateOnNewDocument',
  params: {
    source: %Q{
      (function(XHR) {
        "use strict";

        window.xhrLog = '';

        var open = XHR.prototype.open;
        var send = XHR.prototype.send;

        XHR.prototype.open = function(method, url, async, user, pass) {
          this._url = url; // want to track the url requested
          open.call(this, method, url, async, user, pass);
        };

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

          function onReadyStateChange() {
            if(self.status === 200 && self.readyState == 4 /* complete */) {
              window.xhrLog +=
                '{"data":' + self.responseText + '}***[END]***';
            }
            if(oldOnReadyStateChange) {
              oldOnReadyStateChange();
            }
          }

          if(this.addEventListener) {
            this.addEventListener("readystatechange", onReadyStateChange,
              false);
          } else {
            oldOnReadyStateChange = this.onreadystatechange;
            this.onreadystatechange = onReadyStateChange;
          }
          send.call(this, data);
        }
      })(XMLHttpRequest);
    }
  }
}

driver.send(:bridge).send_command(params)

### Do some stuff here

raw_ajax = driver.execute_script("return window.xhrLog")
ajax_responses = raw_ajax.split('***[END]***')