https://www.balitouryokou.com/jsc/scrolltopcontrol.js

1//** jQuery Scroll to Top Control script- (c) Dynamic Drive DHTML code library: http://www.dynamicdrive.com.
2//** Available/ usage terms at http://www.dynamicdrive.com (March 30th, 09')
3//** v1.1 (April 7th, 09'):
4//** 1) Adds ability to scroll to an absolute position (from top of page) or specific element on the page instead.
5//** 2) Fixes scroll animation not working in Opera. 
6
7//画面をスクロールすると右下に戻るボタンが現れるクエリー
8
9
10var scrolltotop={
11	//startline: Integer. Number of pixels from top of doc scrollbar is scrolled before showing control
12	//scrollto: Keyword (Integer, or "Scroll_to_Element_ID"). How far to scroll document up when control is clicked on (0=top).
13	setting: {startline:50, scrollto: 0, scrollduration:1000, fadeduration:[500, 100]},
14	controlHTML: '<img src="/img/mkUp.gif" style="width:50px; height:50px" />', //HTML for control, which is auto wrapped in DIV w/ ID="topcontrol"
15	controlattrs: {offsetx:10, offsety:10}, //offset of control relative to right/ bottom of window corner
16	anchorkeyword: '#top', //Enter href value of HTML anchors on the page that should also act as "Scroll Up" links
17
18	state: {isvisible:false, shouldvisible:false},
19
20	scrollup:function(){
21		if (!this.cssfixedsupport) //if control is positioned using JavaScript
22			this.$control.css({opacity:0}) //hide control immediately after clicking it
23		var dest=isNaN(this.setting.scrollto)? this.setting.scrollto : parseInt(this.setting.scrollto)
24		if (typeof dest=="string" && jQuery('#'+dest).length==1) //check element set by string exists
25			dest=jQuery('#'+dest).offset().top
26		else
27			dest=0
28		this.$body.animate({scrollTop: dest}, this.setting.scrollduration);
29	},
30
31	keepfixed:function(){
32		var $window=jQuery(window)
33		var controlx=$window.scrollLeft() + $window.width() - this.$control.width() - this.controlattrs.offsetx
34		var controly=$window.scrollTop() + $window.height() - this.$control.height() - this.controlattrs.offsety
35		this.$control.css({left:controlx+'px', top:controly+'px'})
36	},
37
38	togglecontrol:function(){
39		var scrolltop=jQuery(window).scrollTop()
40		if (!this.cssfixedsupport)
41			this.keepfixed()
42		this.state.shouldvisible=(scrolltop>=this.setting.startline)? true : false
43		if (this.state.shouldvisible && !this.state.isvisible){
44			this.$control.stop().animate({opacity:1}, this.setting.fadeduration[0])
45			this.state.isvisible=true
46		}
47		else if (this.state.shouldvisible==false && this.state.isvisible){
48			this.$control.stop().animate({opacity:0}

48, this.setting.fadeduration[1])
49			this.state.isvisible=false
50		}
51	},
52	
53	init:function(){
54		jQuery(document).ready(function($){
55			var mainobj=scrolltotop
56			var iebrws=document.all
57			mainobj.cssfixedsupport=!iebrws || iebrws && document.compatMode=="CSS1Compat" && window.XMLHttpRequest //not IE or IE7+ browsers in standards mode
58			mainobj.$body=(window.opera)? (document.compatMode=="CSS1Compat"? $('html') : $('body')) : $('html,body')
59			mainobj.$control=$('<div id="topcontrol">'+mainobj.controlHTML+'</div>')
60				.css({position:mainobj.cssfixedsupport? 'fixed' : 'absolute', bottom:mainobj.controlattrs.offsety, right:mainobj.controlattrs.offsetx, opacity:0, cursor:'pointer'})
61				.attr({title:'Scroll Back to Top'})
62				.click(function(){mainobj.scrollup(); return false})
63				.appendTo('body')
64			if (document.all && !window.XMLHttpRequest && mainobj.$control.text()!='') //loose check for IE6 and below, plus whether control contains any text
65				mainobj.$control.css({width:mainobj.$control.width()}) //IE6- seems to require an explicit width on a DIV containing text
66			mainobj.togglecontrol()
67			$('a[href="' + mainobj.anchorkeyword +'"]').click(function(){
68				mainobj.scrollup()
69				return false
70			})
71			$(window).bind('scroll resize', function(e){
72				mainobj.togglecontrol()
73			})
74		})
75	}
76}
77
78scrolltotop.init()
79
80
81