ff popunder.js

                var _parent = self,
                    bSimple = false,
                    popunder;
                    
                if (top != self) {
                    try {
                        if (top.document.location.toString()) {
                            _parent = top;
                        }
                    }
                    catch(err) { }
                }
                
                popunder = _parent.window.open(url, '_pu123123123', window_params);
                
                if (popunder) {
                    popunder.blur();
                    if (bSimple) {
                        /* classic popunder, used for ie*/
                        window.focus();
                        try { opener.window.focus(); }
                        catch (err) { }
                    }
                    else {
                        /* popunder for e.g. ff4+, chrome */
                        popunder.init = function(e) {
                            with (e) {
                                (function() {
                                    // if (typeof window.mozPaintCount != 'undefined' || typeof navigator.webkitGetUserMedia === "function") {
                                        //var x = window.open('about:blank');
                                        //x.close();
                                    // }
        
                                    try { opener.window.focus(); }
                                    catch (err) { }
                                })();
                            }
                        };
                        popunder.params = {
                            url: url
                        };
                        popunder.init(popunder);
                    }
                }