浮动模块到底部自动不遮挡

    $(document).on('scroll', function() {
        var scrollH = $(this).scrollTop();
        // 目录悬浮
        var $navdom = $(".scroll-nav");
        if ($navdom.length) {
            // .con 是浮动的元素，会自动计算高度
            var $navcondom = $(".scroll-nav .con");
            var $condom = $('.js-content01');
            var navtop = $navdom[0].offsetTop;
            if (scrollH + $(window).height() / 3 >= navtop) {
                $navcondom.addClass('fixed');
                q = $('body').height() - scrollH - $(".scroll-nav .con").height() - 1000;
                if(q < 0){
                    $(".scroll-nav .con").css('top',q + 'px');
                }
                else
                {
                     $(".scroll-nav .con").css('top','');   
                }
            } else {
                $navcondom.removeClass('fixed');
            }
        }
    })