PhantomJS: Ajax response capture through console.log

gistfile1.js

var page = require('webpage').create();

page.open('http://www.website.com/', function (status) {
  if (status === 'success') {
    captureAjaxResponsesToConsole();
  }
});

function captureAjaxResponsesToConsole() {
  // logs ajax response contents to console so sublime's onConsoleMessage can use the contents
  // credit to Ionuț G. Stan
  // http://stackoverflow.com/questions/629671/how-can-i-intercept-xmlhttprequests-from-a-greasemonkey-script
  page.evaluate(function() {
    (function(open) {
      XMLHttpRequest.prototype.open = function(method, url, async, user, pass) {
        this.addEventListener("readystatechange", function() {
          if (this.readyState === 4) {
            var res={'response':this.responseText, 'url':url};
            console.log(JSON.stringify(res));
          }
        }, false);
        open.call(this, method, url, async, user, pass);
      };
    })(XMLHttpRequest.prototype.open);
    return 1;
  });
}

page.onConsoleMessage = function (msg) {
  var res=JSON.parse(msg);
  console.log('--------------------');
  console.log('URL:' + res.url);
  console.log('Response: ' + res.response);
};

I failed to get success response can you give me example with real variables