var scrolltotop = {
    //Настройки скрипта:
    setting: {
        startline: 100,
        scrollto: 0,
        scrollduration: 1000,
        fadeduration: [500, 100]
    }, //Настройки стилей и выбор картинки:
    controlHTML: '<img src="//f.nodacdn.net/545934" style="width:48px; height:48px; z-index:1000; margin-bottom: 200px;">',
     
    controlattrs: {offsetx: 5, offsety: 5}, //offset of control relative to right/ bottom of window corner
    anchorkeyword: '#top', //Enter href value of HTML anchors on the page that should also act as "Scroll Up" links
 
    state: {isvisible: false, shouldvisible: false},
 
    scrollup: function() {
        if (!this.cssfixedsupport)
            this.$control.css({opacity: 0}) //hide control immediately after clicking it
        var dest = isNaN(this.setting.scrollto) ? this.setting.scrollto : parseInt(this.setting.scrollto);
        if (typeof dest == "string" && jQuery('#' + dest).length == 1) //check element set by string exists
            dest = jQuery('#' + dest).offset().top;
        else
            dest = 0;
        this.$body.animate({scrollTop: dest}, this.setting.scrollduration);
    },
 
    keepfixed: function() {
        var $window = jQuery(window);
        var controlx = $window.scrollLeft() + $window.width() - this.$control.width() - this.controlattrs.offsetx;
        var controly = $window.scrollTop() + $window.height() - this.$control.height() - this.controlattrs.offsety;
        this.$control.css({left: controlx + 'px', top: controly + 'px'});
    },
 
    togglecontrol: function() {
        var scrolltop = jQuery(window).scrollTop();
        if (!this.cssfixedsupport)
            this.keepfixed();
        this.state.shouldvisible = (scrolltop >= this.setting.startline) ? true : false;
        if (this.state.shouldvisible && !this.state.isvisible) {
            this.$control.stop().animate({opacity: 1}, this.setting.fadeduration[0]);
            this.state.isvisible = true;
        } else if (this.state.shouldvisible == false && this.state.isvisible) {
            this.$control.stop().animate({opacity: 0}, this.setting.fadeduration[1]);
            this.state.isvisible = false;
        }
    },
     
    init: function() {
        jQuery(document).ready(function($) {
            var mainobj = scrolltotop;
            var iebrws = document.all;
            mainobj.cssfixedsupport = !iebrws || iebrws && document.compatMode == "CSS1Compat" && window.XMLHttpRequest; //not IE or IE7+ browsers in standards mode
            mainobj.$body = (window.opera) ? (document.compatMode == "CSS1Compat" ? $('html') : $('body')) : $('html,body');
            mainobj.$control = $('<div id="topcontrol">' + mainobj.controlHTML + '</div>')
                .css({
                    position: mainobj.cssfixedsupport ? 'fixed' : 'absolute',
                    bottom: mainobj.controlattrs.offsety,
                    right: mainobj.controlattrs.offsetx,
                    opacity: 0,
                    cursor: 'pointer',
                    zIndex: 998, // Добавляем z-index для отображения поверх других элементов
                    transition: 'transform 0.3s ease', // Плавный переход для анимации
                })
                .attr({title: 'Вверх'})
                .hover(
                    function() { $(this).css('transform', 'scale(1.2)'); }, // Увеличение при наведении
                    function() { $(this).css('transform', 'scale(1)'); } // Возврат к норме
                )
                .click(function() { mainobj.scrollup(); return false; })
                .appendTo('body');
            if (document.all && !window.XMLHttpRequest && mainobj.$control.text() != '') //loose check for IE6 and below, plus whether control contains any text
                mainobj.$control.css({width: mainobj.$control.width()}); //IE6- seems to require an explicit width on a DIV containing text
            mainobj.togglecontrol();
            $('a[href="' + mainobj.anchorkeyword + '"]').click(function() {
                mainobj.scrollup();
                return false;
            });
            $(window).bind('scroll resize', function(e) {
                mainobj.togglecontrol();
            });
        });
    }
}

scrolltotop.init();