浮动导航

//初始化全局变量GLOBAL.onscrollY.thisy【滚动的高度】
GLOBAL.namespace('onscrollY'); 
GLOBAL.onscrollY.thisy=0;

$(window).resize(function(){
    GLOBAL.onscrollY.thisy = (document.body.scrollTop||document.documentElement.scrollTop);
});
$(window).scroll(function(){
    GLOBAL.onscrollY.thisy = (document.body.scrollTop||document.documentElement.scrollTop);
});
//【floatMenu】超过【Gover】时增加类【onFloat】——可用于浮动导航 

//实例调用 onFixed('.floatMenu','#Gover','onFloat');



function onFixed(floatMenu,Gover,onClass){
    this.floatMenu=$(floatMenu);
    this.Gover=$(Gover);
    this.onClass=onClass;
    $(window).scroll(function(){
        if( GLOBAL.onscrollY.thisy >this.Gover.offset().top ){    
            this.floatMenu.addClass(this.onClass);
        }else{
            this.floatMenu.removeClass(this.onClass);
        }
    });
}