var scrolltotop = {
    setting: {
        startline: 100,
        scrollto: 0,
        scrollduration: 1000,
        fadeduration: [500, 100]
    },
    controlHTML: '<img src="images/up.png" style="width:25px; height:25px" />',
    controlattrs: {
        offsetx: 5,
        offsety: 5
    },
    anchorkeyword: "#top",
    state: {
        isvisible: false,
        shouldvisible: false
    },
    scrollup: function () {
        if (!this.cssfixedsupport) {
            this.$control.css({
                opacity: 0
            })
        }
        var a = isNaN(this.setting.scrollto) ? this.setting.scrollto : parseInt(this.setting.scrollto);
        if (typeof a == "string" && jQuery("#" + a).length == 1) {
            a = jQuery("#" + a).offset().top
        } else {
            a = 0
        }
        this.$body.animate({
            scrollTop: a
        }, this.setting.scrollduration)
    },
    keepfixed: function () {
        var c = jQuery(window);
        var b = c.scrollLeft() + c.width() - this.$control.width() - this.controlattrs.offsetx;
        var a = c.scrollTop() + c.height() - this.$control.height() - this.controlattrs.offsety;
        this.$control.css({
            left: b + "px",
            top: a + "px"
        })
    },
    togglecontrol: function () {
        var a = jQuery(window).scrollTop();
        if (!this.cssfixedsupport) {
            this.keepfixed()
        }
        this.state.shouldvisible = (a >= this.setting.startline) ? true : false;
        if (this.state.shouldvisible && !this.state.isvisible) {
            this.$control.stop().animate({
                opacity: 1
            }, this.setting.fadeduration[0]);
            this.state.isvisible = true
        } else {
            if (this.state.shouldvisible == false && this.state.isvisible) {
                this.$control.stop().animate({
                    opacity: 0
                }, this.setting.fadeduration[1]);
                this.state.isvisible = false
            }
        }
    },
    init: function () {
        jQuery(document).ready(function (c) {
            var a = scrolltotop;
            var b = document.all;
            a.cssfixedsupport = !b || b && document.compatMode == "CSS1Compat" && window.XMLHttpRequest;
            a.$body = (window.opera) ? (document.compatMode == "CSS1Compat" ? c("html") : c("body")) : c("html,body");
            a.$control = c('<div id="topcontrol">' + a.controlHTML + "</div>").css({
                position: a.cssfixedsupport ? "fixed" : "absolute",
                bottom: a.controlattrs.offsety,
                right: a.controlattrs.offsetx,
                opacity: 0,
                cursor: "pointer"
            }).attr({
                title: "Scroll Back to Top"
            }).click(function () {
                a.scrollup();
                return false
            }).appendTo("body");
            if (document.all && !window.XMLHttpRequest && a.$control.text() != "") {
                a.$control.css({
                    width: a.$control.width()
                })
            }
            a.togglecontrol();
            c('a[href="' + a.anchorkeyword + '"]').click(function () {
                a.scrollup();
                return false
            });
            c(window).bind("scroll resize", function (d) {
                a.togglecontrol()
            })
        })
    }
};
scrolltotop.init();