滚动到顶部-jquery.scrolltotop.js

使用教程：
直接粘贴下面的代码，作为一个jquery.scrolltotop.js引入
配置参数：scrolltotop.setting.startline = 100; // 还有controlHTML参数等等可配置
初始化插件： scrolltotop.init();
//** jQuery Scroll to Top Control script- (c) Dynamic Drive DHTML code library: http://www.dynamicdrive.com.
//** Available/ usage terms at http://www.dynamicdrive.com (March 30th, 09')
//** v1.1 (April 7th, 09'):
//** 1) Adds ability to scroll to an absolute position (from top of page) or specific element on the page instead.
//** 2) Fixes scroll animation not working in Opera. 


var scrolltotop = {
    setting: {
        startline: 1, // 开始出现回到顶部控件的scrollTop值
        scrollto: 0,
        scrollduration: 80,
        fadeduration: [500, 100]
    },

    controlHTML: '<img src="/img/gotop.gif" style="width:31px; height:31px;" />', //HTML for control, which is auto wrapped in DIV w/ ID="topcontrol"


    controlattrs: {
        offsetx: 100,
        offsety: 165
    }, //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) //if control is positioned using JavaScript
            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.$control.stop().show();
            this.state.isvisible = true
        } else if (this.state.shouldvisible == false && this.state.isvisible) {
            this.$control.stop().hide();
            this.state.isvisible = false
        }
    },
    offset: function(x, y) {
        scrolltotop.controlattrs.offsetx = x;
        scrolltotop.controlattrs.offsety = y;
    },
    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 = $('<div id="topcontrol">' + mainobj.controlHTML + '</div>')
                .css({
                    position: mainobj.cssfixedsupport ? 'fixed' : 'absolute',
                    bottom: mainobj.controlattrs.offsety,
                    right: mainobj.controlattrs.offsetx,
                    display: 'none',
                    cursor: 'pointer'
                })
                .attr({
                    title: '回到顶部'
                })
                .click(function() {
                    mainobj.scrollup();
                    return false
                })
                .appendTo('body')
            if (document.all && !window.XMLHttpRequest && mainobj.$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()
            })
        })
    }
};
来源：oschina
链接：https://my.oschina.net/u/1414034/blog/268850
标签
滚动到顶部
scrolltotop