( function() {//desktop floating top bar
	//if( (SysPC==true  ) && (SysIe==undefined || SysIe>=9) ){//目前只支持PC IE9+和现代浏览器
		var masthead=checkElement("topNavBar");
		var dropdownTrigger=checkElement("topNavBar-menu");
		var mastHeight = "50";
		function runscroll(){
			//if (getViewPortSize().x>1200 ){
				if( getScrollOffsets().y >= 800 ){
					addClass( masthead , "scroll") ;
				} else {
					removeClass( masthead , "scroll") ;
					removeClass( menuDwop , "stay") ;
					removeClass( fullMask , "stay") ;
				}
			//}
		}
		addEvent(window, "scroll", function(){
			runscroll();
		});
		addEvent(window, "resize", function(){
			runscroll();
		});
		

		var menuBtn=checkElement("topNavBar-menu");
		var menuDwop=checkElement("topNavBar-dropdown");
		var fullMask=checkElement("fullMask");
		function swichDropdownMenu(){
			if( hasClass( menuDwop , "stay") ){
				removeClass( menuDwop , "stay") ;
				removeClass( fullMask , "stay") ;
				removeClass( dropdownTrigger , "stay") ;
			}else{
				addClass( menuDwop , "stay") ;
				addClass( fullMask , "stay") ;
				addClass( dropdownTrigger , "stay") ;
			}
		}
		addEvent(menuBtn, "click", swichDropdownMenu );
		addEvent(fullMask, "click", function(){
			removeClass( menuDwop , "stay") ;
			removeClass( fullMask , "stay") ;
			removeClass( dropdownTrigger , "stay") ;
		} );

		runscroll();


	//}
} )();