fixed

!(function(){
    $.fn.affix = function(options){
        var defualtOption = {
            top:0,
            container:$("html, body"),
            bottom:0
        }
        var option = $.extend( defualtOption, options);
        var offsetTop = $(this).offset().top;
        var height = option.container.height();
        var cOffsetTop = option.container.offset().top;
        var limmit = height + cOffsetTop - option.bottom;
        var _this = this;
        $(window).on("scroll",function(){
            var scorllTop = $(window).scrollTop();
            console.log("dddd")
            console.log(offsetTop)
            console.log(scorllTop + cOffsetTop)
            if(offsetTop < scorllTop  && scorllTop < limmit){
                if(window.XMLHttpRequest){
                    $(_this).css({
                        position:"fixed",
                        top:0
                    })
                }else{
                    $(_this).css({
                        position:"absolute",
                        top: offsetTop - scorllTop
                    })
                }
            }else{
                $(_this).css({
                    position:"static"
                })
            }
        })
    }
})(jQuery)