<script>
    jQuery(document).ready(function($) {
        try{
            var f1 = $('.j_FloorItem[data-slide="1"]').offset().top;
            var fs = $('.navigation').children().size();
            var fss = new Array();
            for (i = 0; i < fs; i++) {
                j = i + 1;
                fss[i] = $('.j_FloorItem[data-slide="' + j + '"]').offset().top;
            }



            $(window).scroll(function(){
                var currentTOP = $(window).scrollTop();
                if(currentTOP>f1-30){
                    $("#nav").show();
                }else{
                    $("#nav").hide();
                }
                if (currentTOP <= f1) {
                    $('.navigation li').removeClass('current');
                    $('.navigation li[data-slide="1"]').addClass('current');
                    return;
                }else{
                    changefl(getFloor(currentTOP));
                }
            });


            function getFloor(fh){
                if(fs==0||fh<=f1){
                    return 1;
                }
                if(fh>=fss[fs-1]){
                    return fs;
                }
                for (k=0; k<fs;k++) {
                    if(fh>fss[k]&&fh<fss[k+1]){
                        return k+1;
                    }
                }
            }

            function changefl(fno){
                $('.navigation li').removeClass('current');
                $('.navigation li[data-slide="'+fno+'"]').addClass('current');
            }

        }catch(e){
            console.log(e);
        }
    });

    function gotop() {
        $('body,html').animate({
            scrollTop : 0
        }, 800);
    }
    function gotofloor(thiz) {
        $("li[class='current']").attr('class', '');
        $(thiz).attr("class", "current");
        dataslide = $(thiz).attr('data-slide');
        var pos = $('.j_FloorItem[data-slide="' + dataslide + '"]').offset().top;// 获取该点到头部的距离
        $("html,body").animate({
            scrollTop : pos
        },300);
    }
</script>