// JSX

        // hide/close tab event -> save localStorage
        var pageVisibilityEvent = new PageVisibilityEvent();

        pageVisibilityEvent.on(function(pageHide:boolean):void {
            if (pageHide) {
                ;
            }
        });

// JSX
// ----------------------------------------------
/*
+-------------------+------------------+----------+----------+------------------+
| OS, Browser       |  load            | hide tab | show tab | close tab        |
+-------------------+------------------+----------+----------+------------------+
| iOS 5.1 Safari    | pageshow         | pagehide | pageshow |                  |
| iOS 6.1 Safari    | pageshow         | pagehide | pageshow |                  |
| Mac Safari 6.0.4  | pageshow         | blur     | focus    |                  |
| Mac Chrome 26     | visibilitychange | blur     | focus    | visibilitychange |
| Android Chrome 27 | visibilitychange | blur     | focus    | visibilitychange |
| Android 4.0.1     | pageshow         | blur     | focus    | pagehide         |
| Android 2.3.6     | pageshow         | (none)   | (none)   | pagehide         |
+-------------------+------------------+----------+----------+------------------+
 */
/*
//  var pageVisibilityEvent = new PageVisibilityEvent();
//
//  pageVisibilityEvent.on(function(pageHide:boolean):void {
//      log(pageHide ? "page hide" : "page show");
//  });
 */
class PageVisibilityEvent {
    var _hidden = false;                    // Boolean - current PageVisibility state
    var _callback = null:function(:boolean):void; // Function - callback

    function on(callback:function(pageHide:boolean):void):void {
        this._callback = callback;
        this._handler(true);
    }
    function off():void {
        this._callback = null;
        this._handler(false);
    }
    function isHidden():boolean {
        return this._hidden;
    }
    function _handler(attach:boolean):void { // @arg Boolean(= false): true is attach event
        var that = this;
        var window   = js.global["window"]   as __noconvert__ Window;
        var document = js.global["document"] as __noconvert__ HTMLDocument;

        function _handlePageVisibility(event:Event):void {
            that._callback(that._hidden = document["hidden"] || document["webkitHidden"] || false);
        }
        function _handlePageShow(event:Event):void {
            that._hidden = event.type == "pagehide";
            that._callback(that._hidden);
        }
        function _handleFocus(event:Event):void {
            that._hidden = event.type == "blur";
            that._callback(that._hidden);
        }

        if ( "hidden" in document as __noconvert__ Map.<variant> ) {
            if (attach) { document.addEventListener("visibilitychange", _handlePageVisibility, false); }
                   else { document.removeEventListener("visibilitychange", _handlePageVisibility, false); }
        } else if ( "webkitHidden" in document as __noconvert__ Map.<variant> ) {
            if (attach) { document.addEventListener("webkitvisibilitychange", _handlePageVisibility, false); }
                   else { document.removeEventListener("webkitvisibilitychange", _handlePageVisibility, false); }
        } else {
            if ( /iPhone|iPad|iPod/.test(window.navigator.userAgent) ) {
                if (attach) { window.addEventListener("pageshow", _handlePageShow); }
                       else { window.removeEventListener("pageshow", _handlePageShow); }
                if (attach) { window.addEventListener("pagehide", _handlePageShow); }
                       else { window.removeEventListener("pagehide", _handlePageShow); }
            } else {
                if (attach) { window.addEventListener("focus", _handlePageShow); }
                       else { window.removeEventListener("focus", _handlePageShow); }
                if (attach) { window.addEventListener("blur", _handleFocus); }
                       else { window.removeEventListener("blur", _handleFocus); }
            }
        }
    }
}