function doPopunder(url, windowName) {
    var b = "toolbar=1,statusbar=1,resizable=1,scrollbars=1,menubar=1,location=1,directories=0";
    if (navigator.userAgent.indexOf("MSIE") != -1) {
        b = "toolbar=1,statusbar=1,resizable=1,scrollbars=1,menubar=0,location=1,directories=0";
    } else if (navigator.userAgent.indexOf("Chrome") != -1) {
        b = "scrollbar=yes";
    }

    var a = window.open("", windowName, b + ",height=800,width=1100");
    try {
        if (a.window.location.href.substr(0,4) != 'http') {
            a.window.location.href = url;
        }
    } catch (c) {
        
    }
    // some 'magic' to make the popunder work in FF
    if (typeof window.mozPaintCount != "undefined") {
        try {
            a.window.open("about:blank").close();
            a.opener.window.focus()
        } catch (c) {}
    } else {
        window.focus();
    }
}


function popunder(from, params, channel) {
    if (window.opener || (document.cookie && document.cookie.search('cvpopunder=no') != -1)) {
        return;
    }
    
    channel = (typeof channel === 'string' ? channel.toLowerCase() : '');

    var makeChannelUrl = (function(channel) {
        return function(url) {
            switch (channel) {
                case 'pauschal':
                    return url + 'engine=pauschal&';
                    break;
                case 'eigeneanreise': // hotels von restplatzboerse
                case 'hotel':
                    return url.replace('index.php', 'erde/index.php');
                    break;
                case 'ferienhauser':
                case 'fewo':
                    return url.replace('index.php', 'fewo/index.php');
                    break;
                case 'flug':
                    return url + 'nurflug=1&';
                    break;
                case 'lastminute':
                default:
                    return url;
                    break;
            }
        }
    }(channel));

    var config = {
        'ferien.de': {
            sites: ['weg.de','restplatzboerse.de'],
            tracking_param: 'bas~popunder~ferien'
        },
        'restplatzboerse.de': {
            sites: ['weg.de','ferien.de'],
            tracking_param: 'bas~popunder~restplatzboerse'
        }
    };

    var mapping = {
        'weg.de': {
            raw_url: 'http://lastminute.weg.de/booking/weg_tt/index.php?',
            KID: '692000'
        },
        'restplatzboerse.de': {
            raw_url: 'http://lastminute.restplatzboerse.de/booking/ferienPartner2/index.php?',
            KID: '626102'
        },
        'ferien.de': {
            raw_url: 'http://lastminute.ferien.de/booking/ferien_tt/index.php?',
            KID: '626150'
        }
    };

    var sites = config[from].sites;
    params.ext_cid = config[from].tracking_param;

    for (var i = 0, s; s = sites[i]; ++i) {
        if (s in mapping) {
            params.KID = mapping[s].KID;
            var url = makeChannelUrl(mapping[s].raw_url);
            doPopunder(url + dojo.objectToQuery(params), 'cvpopunder' + params.KID);
        }
    }
}