브라우저 전환 창 이벤트

var pageVisibility = (function() {
    var prefixSupport, keyWithPrefix = function(prefix, key) {
        if (prefix !== "") {
            //  
            return prefix + key.slice(0,1).toUpperCase() + key.slice(1);    
        }
        return key;
    };
    var isPageVisibilitySupport = (function() {
        var support = false;
        if (typeof window.screenX === "number") {
            ["webkit", "moz", "ms", "o", ""].forEach(function(prefix) {
                if (support == false && document[keyWithPrefix(prefix, "hidden")] != undefined) {
                    prefixSupport = prefix;
                    support = true;   
                }
            });        
        }
        return support;
    })();
    
    var isHidden = function() {
        if (isPageVisibilitySupport) {
            return document[keyWithPrefix(prefixSupport, "hidden")];
        }
        return undefined;
    };
    
    var visibilityState = function() {
        if (isPageVisibilitySupport) {
            return document[keyWithPrefix(prefixSupport, "visibilityState")];
        }
        return undefined;
    };
    
    return {
        hidden: isHidden(),   //  tab true， false
        visibilityState: visibilityState(),   //  tab hidden， visible
        visibilitychange: function(fn, usecapture) {   //  tab 
            usecapture = undefined || false;
            if (isPageVisibilitySupport && typeof fn === "function") {
                return document.addEventListener(prefixSupport + "visibilitychange", function(evt) {
                    this.hidden = isHidden();
                    this.visibilityState = visibilityState();
                    fn.call(this, evt);
                }.bind(this), usecapture);
            }
            return undefined;
        }
    };    
})(undefined);

pageVisibility.visibilitychange(function(){
    if(!pageVisibility.hidden){   //  
        console.log(" ...");
    }
})