function checkAdvert(bannerKey) {
    function bannerAction(action, key, frameElement) {
        if (window.top.bannerHelper && window.top.bannerHelper[action] && typeof (window.top.bannerHelper[action]) === "function") {
            window.top.bannerHelper[action](key, frameElement);
        }
    }

    var counter = 20,
        interval = setInterval(function () {
        --counter;
        if (counter < 1) clearInterval(interval);
        try {


            var imgsStop = document.getElementsByTagName("img");
            for (var j = 0; j < imgsStop.length; j++) {
                var src = imgsStop[j].src;
                if (src.indexOf("default.jpg") >= 0 || src.indexOf("transparent.gif") >= 0 && (imgsStop[j].width == "0" && imgsStop[j].height == "0" || (imgsStop[j].getAttribute("width") == "0" && imgsStop[j].getAttribute("height") == "0"))) {
                    bannerAction("unload", bannerKey, window.frameElement);

                    clearInterval(interval);
                    return;
                }
            }

            var tags = ["object", "embed", "p", "img", "ul", "iframe", "table", "canvas"];
            var boolDisplayBlock = false;
            for (var i = 0; i < tags.length; i++) {
                var f = document.getElementsByTagName(tags[i]);
                for (var k = 0; k < f.length; k++) {
                    if (!(f[k].style.display == "none" || f[k].style.visibility == "hidden")) {
                        if (tags[i] !== "iframe") {
                            boolDisplayBlock = true;
                            break;
                        } else if (parseInt(f[k].style.width) > 1 || parseInt(f[k].style.height) > 1) {
                            boolDisplayBlock = true;
                            break;
                        }
                    }
                }
            }

            if (!boolDisplayBlock) {
                if (document.getElementsByClassName("AdFox_banner_html5").length > 0) {
                    boolDisplayBlock = true;
                }
            }

            if (boolDisplayBlock) {
                if (window.frameElement) {
                    bannerAction("load", bannerKey, window.frameElement);
                    window.frameElement.style.visibility = "";
                    window.frameElement.style.position = "relative";
                    window.frameElement.style.zIndex = 0;
                    clearInterval(interval);
                }
            } else if (counter < 1) {
                bannerAction("unload", bannerKey, window.frameElement);
            }

        } catch (e) {
            // ignore
        }
    }, 100);
};