var getNumberOfItems = function(casper) {
    listItems = casper.evaluate(function () {
        var nodes = document.querySelectorAll('li');
        return Array.prototype.map.call(nodes, function(node) {
            return node.getAttribute('data-bt');
        });
    });
    casper.echo(listItems.length);
    return listItems.length;
}
casper.start(url, function() {

    this.userAgent('Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html');

    var js = this.evaluate(function() {
        return document;
    });
    var source = js.all[0].outerHTML;

    if (source.match(/captcha/g)) {
        this.echo('Captcha found, logging in');
        this.evaluate(function() {
            document.getElementById("email").value="***";
            document.getElementById("pass").value="***";
            document.getElementById("loginbutton").children[0].click();

        });
    }
    this.label('LOOP_START');
    var info = getNumberOfItems(this);
    this.scrollToBottom();

    this.waitFor(function check(){
        casper.echo('waitFor');
        return info != getNumberOfItems(casper);
    }, function then(){
        casper.echo('then');
        if (getNumberOfItems(casper)<50) this.goto('LOOP_START');
    }, function onTimeout(){
        casper.echo("Timout reached");
    }, 20000);

casper.evaluate(function() {
   window.document.body.scrollTop = document.body.scrollHeight;
});

casper.page.scrollPosition = { top: casper.page.scrollPosition["top"] + 4000, left: 0 };