make a full picture of carmack tweets

scroll_twitter.js

var page = require('webpage').create();
page.open('http://twitter.com/ID_AA_Carmack', function (status) {
    if (status !== 'success') {
        console.log('Unable to access network');
    } else {


        var hitRockBottom = false;
        while (!hitRockBottom) {
                //scroll the page (not sure if this is the best way to do so...)
                 page.scrollPosition = { top: page.scrollPosition + 1000, left: 0 };

                // Check if we've hit the bottom
                 hitRockBottom = page.evaluate(function() {
                         return document.querySelector(".has-more-items") === null;
                            });
                             }

                page.render('output5.jpg')

        var ua = page.evaluate(function () {
            return document.getElementById('page-container').innerHTML;
        });
        console.log(ua);

    }
    phantom.exit();
});

scrolling not working.can't get any output.