https://yokubo-no-machi.com/js/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
7var scrolltotop={
8	//startline: Integer. Number of pixels from top of doc scrollbar is scrolled before showing control
9	//scrollto: Keyword (Integer, or "Scroll_to_Element_ID"). How far to scroll document up when control is clicked on (0=top).
10	setting: {startline:100, scrollto: 0, scrollduration:1000, fadeduration:[500, 100]},
11	controlHTML: '<img src="/images/btn_modoru.png" style="width:38px; height:50px" />', //HTML for control, which is auto wrapped in DIV w/ ID="topcontrol"
12	controlattrs: {offsetx:0, offsety:50}, //offset of control relative to right/ bottom of window corner
13	anchorkeyword: '#top', //Enter href value of HTML anchors on the page that should also act as "Scroll Up" links
14
15	state: {isvisible:false, shouldvisible:false},
16
17	scrollup:function(){
18		if (!this.cssfixedsupport) //if control is positioned using JavaScript
19			this.$control.css({opacity:0}) //hide control immediately after clicking it
20		var dest=isNaN(this.setting.scrollto)? this.setting.scrollto : parseInt(this.setting.scrollto)
21		if (typeof dest=="string" && jQuery('#'+dest).length==1) //check element set by string exists
22			dest=jQuery('#'+dest).offset().top
23		else
24			dest=0
25		this.$body.animate({scrollTop: dest}, this.setting.scrollduration);
26	},
27
28	keepfixed:function(){
29		var $window=jQuery(window)
30		var controlx=$window.scrollLeft() + $window.width() - this.$control.width() - this.controlattrs.offsetx
31		var controly=$window.scrollTop() + $window.height() - this.$control.height() - this.controlattrs.offsety
32		this.$control.css({left:controlx+'px', top:controly+'px'})
33	},
34
35	togglecontrol:function(){
36		var scrolltop=jQuery(window).scrollTop()
37		if (!this.cssfixedsupport)
38			this.keepfixed()
39		this.state.shouldvisible=(scrolltop>=this.setting.startline)? true : false
40		if (this.state.shouldvisible && !this.state.isvisible){
41			this.$control.stop().animate({opacity:1}, this.setting.fadeduration[0])
42			this.state.isvisible=true
43		}
44		else if (this.state.shouldvisible==false && this.state.isvisible){
45			this.$control.stop().animate({opacity:0}

45, this.setting.fadeduration[1])
46			this.state.isvisible=false
47		}
48	},
49	
50	init:function(){
51		jQuery(document).ready(function($){
52			var mainobj=scrolltotop
53			var iebrws=document.all
54			mainobj.cssfixedsupport=!iebrws || iebrws && document.compatMode=="CSS1Compat" && window.XMLHttpRequest //not IE or IE7+ browsers in standards mode
55			mainobj.$body=(window.opera)? (document.compatMode=="CSS1Compat"? $('html') : $('body')) : $('html,body')
56			mainobj.$control=$('<div id="topcontrol">'+mainobj.controlHTML+'</div>')
57				.css({position:mainobj.cssfixedsupport? 'fixed' : 'absolute', bottom:mainobj.controlattrs.offsety, right:mainobj.controlattrs.offsetx, opacity:0, cursor:'pointer','z-index':"1000"})
58				.attr({title:'Scroll Back to Top'})
59				.click(function(){mainobj.scrollup(); return false})
60				.appendTo('body')
61			if (document.all && !window.XMLHttpRequest && mainobj.$control.text()!='') //loose check for IE6 and below, plus whether control contains any text
62				mainobj.$control.css({width:mainobj.$control.width()}) //IE6- seems to require an explicit width on a DIV containing text
63			mainobj.togglecontrol()
64			$('a[href="' + mainobj.anchorkeyword +'"]').click(function(){
65				mainobj.scrollup()
66				return false
67			})
68			$(window).bind('scroll resize', function(e){
69				mainobj.togglecontrol()
70			})
71		})
72	}
73}
74
75scrolltotop.init()