Up and down button. with memorization of the place where was scroll up - page scrolling down does not work

Button up and down page. when you press the scroll down button, there is no reaction to the button.

the script remembers the position where you scroll down.

;(function($){var h=$.scrollTo=function(a,b,c){$(window).scrollTo(a,b,c)};h.defaults={axis:'xy',duration:parseFloat($.fn.jquery)>=1.3?0:1,limit:true};h.window=function(a){return $(window)._scrollable()};$.fn._scrollable=function(){return this.map(function(){var a=this,isWin=!a.nodeName||$.inArray(a.nodeName.toLowerCase(),['iframe','#document','html','body'])!=-1;if(!isWin)return a;var b=(a.contentWindow||a).document||a.ownerDocument||a;return/webkit/i.test(navigator.userAgent)||b.compatMode=='BackCompat'?b.body:b.documentElement})};$.fn.scrollTo=function(e,f,g){if(typeof f=='object'){g=f;f=0}if(typeof g=='function')g={onAfter:g};if(e=='max')e=9e9;g=$.extend({},h.defaults,g);f=f||g.duration;g.queue=g.queue&&g.axis.length>1;if(g.queue)f/=2;g.offset=both(g.offset);g.over=both(g.over);return this._scrollable().each(function(){if(e==null)return;var d=this,$elem=$(d),targ=e,toff,attr={},win=$elem.is('html,body');switch(typeof targ){case'number':case'string':if(/^([+-]=)?\d+(\.\d+)?(px|%)?$/.test(targ)){targ=both(targ);break}targ=$(targ,this);if(!targ.length)return;case'object':if(targ.is||targ.style)toff=(targ=$(targ)).offset()}$.each(g.axis.split(''),function(i,a){var b=a=='x'?'Left':'Top',pos=b.toLowerCase(),key='scroll'+b,old=d[key],max=h.max(d,a);if(toff){attr[key]=toff[pos]+(win?0:old-$elem.offset()[pos]);if(g.margin){attr[key]-=parseInt(targ.css('margin'+b))||0;attr[key]-=parseInt(targ.css('border'+b+'Width'))||0}attr[key]+=g.offset[pos]||0;if(g.over[pos])attr[key]+=targ[a=='x'?'width':'height']()*g.over[pos]}else{var c=targ[pos];attr[key]=c.slice&&c.slice(-1)=='%'?parseFloat(c)/100*max:c}if(g.limit&&/^\d+$/.test(attr[key]))attr[key]=attr[key]<=0?0:Math.min(attr[key],max);if(!i&&g.queue){if(old!=attr[key])animate(g.onAfterFirst);delete attr[key]}});animate(g.onAfter);function animate(a){$elem.animate(attr,f,g.easing,a&&function(){a.call(this,e,g)})}}).end()};h.max=function(a,b){var c=b=='x'?'Width':'Height',scroll='scroll'+c;if(!$(a).is('html,body'))return a[scroll]-$(a)[c.toLowerCase()]();var d='client'+c,html=a.ownerDocument.documentElement,body=a.ownerDocument.body;return Math.max(html[scroll],body[scroll])-Math.min(html[d],body[d])};function both(a){return typeof a=='object'?a:{top:a,left:a}}})(jQuery);
 
jQuery.extend(jQuery.fn, {
        toplinkwidth: function(){
                totalContentWidth = jQuery('#content').outerWidth();
                totalTopLinkWidth = jQuery('#arrows-updow').children('a').outerWidth(true);
                h = jQuery(window).width()/2-totalContentWidth/2-totalTopLinkWidth;
                if(h<0){
                        jQuery(this).hide();
                } else {
                        if(jQuery(window).scrollTop() >= 1){
                                jQuery(this).show();
                        };
                }
        }
});
 
jQuery(function($){
        var topLink = $('#arrows-updow');
        topLink.toplinkwidth();
        $(window).resize(function(){
                topLink.toplinkwidth();
        });
        $(window).scroll(function() {
                if($(window).scrollTop() >= 1) {
                        topLink.fadeIn(300).children('a').html('наверх').parent().removeClass('bottom_button').addClass('top_button');
                } else {
                        topLink.children('a').html('вниз').parent().removeClass('top_button').addClass('bottom_button');
                }
        });
        topLink.click(function(e) {
                if($(this).hasClass('bottom_button')){
                        $("body").scrollTo( pos + 'px', 500 );
                } else{
                        pos = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;
                        $("body,html").animate({scrollTop: 0},500);
                }
                return false;
        });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.7/jquery.min.js"></script>
<div class="btn-top" id="arrows-updow"><a href="#top"><svg class="icon icon-updow"><use xlink:href="#icon-updow"></use></svg></a></div>

think of a professional in JS understand what the problem is, I really hope.

I apologize for my English(