Adsense fallback

adsense.fallback.js

(function(callback){
    var findParent = function (elem, selector) {
        if( !elem ) return null;
        var parent = elem.parentNode;
        if (parent.matches(selector)) return parent;
        return findParent(parent, selector);
    }
    var findQueryFrame = function(id){
        var selector = '[data-google-query-id="'+id+'"]';
        var frame    = document.querySelector(selector);
        if( frame ) return frame;
        frame     = [].slice.call(document.querySelectorAll('iframe')).find(function(el,item){
            try{
                item = el.contentWindow.document;
                if(item.querySelector(selector)){
                   return true;
                }
            } catch(e){}
            return item;
        });
        return frame;
    }
    function adFallback(data){
        var config = {qid:false,r_nh:false};
        data.key_value.forEach(function(item) {
            config[item.key] = item.value;
        });
        if(config.r_nh !== '0'){
            return false;
        }
        var frame    = findQueryFrame(config.qid);
        var slot     = findParent(frame,'.adsbygoogle');
        if( slot === null ) return false;
        callback(slot,frame);
    }
    window.addEventListener('message',function(event){
        var data  = {msg_type: false};
        try{
            data = JSON.parse(event.data);
        } catch(e){

        }
        if(data.googMsgType === 'sth' && data.msg_type === 'resize-me'){
            setTimeout(function(){
                adFallback(data);
            });
        }
    });
})(function(slot,frame){
    var fallback = document.createElement('ins');
    fallback.className = 'banner-fallback';
    fallback.style.height = [frame.clientHeight,'px'].join('');
    slot.parentNode.replaceChild(fallback,slot);
});