https://faje.or.jp/js/smoothScroll.js

1/*--------------------------------------------------------------------------*
2 *  
3 *  SmoothScroll JavaScript Library beta1
4 *  
5 *  MIT-style license. 
6 *  
7 *  2007 Kazuma Nishihata 
8 *  http://www.webcreativepark.net
9 *  
10 *--------------------------------------------------------------------------*/
11 
12new function(){
13
14	/*
15	 *イベント追加用
16	  -------------------------------------------------*/
17	function addEvent(elm,listener,fn){
18		try{ // IE
19			elm.addEventListener(listener,fn,false);
20		}catch(e){
21			elm.attachEvent(
22				"on"+listener
23				,function(){
24					fn.apply(elm,arguments)
25				}
26			);
27		}
28	}
29
30	/*
31	 *スムーズスクロール
32	  -------------------------------------------------*/
33	function SmoothScroll(a){
34		if(document.getElementById(a.rel.replace(/.*\#/,""))){
35			var e = document.getElementById(a.rel.replace(/.*\#/,""));
36		}else{
37			return;
38		}
39		
40		//移動位置
41		var end=e.offsetTop
42		//現在位置
43		var start=window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0;
44		
45		var flag=(end<start)?"up":"down";
46
47		function scrollMe(start,end,flag) {
48
49			setTimeout(
50				function(){
51					if(flag=="up" && start >= end){
52						start=start-(start-end)/20-1;
53						window.scrollTo(0,start)
54						arguments.callee(start,end,flag);
55
56					}else if(flag=="down" && start <= end){
57						start=start+(end-start)/20+1;
58
59						window.scrollTo(0,start)
60						arguments.callee(start,end,flag);
61
62					}else{
63						scrollTo(0,end);
64					}
65				}
66				,200
67			);
68			
69		}
70		scrollMe(start,end,flag)
71	}
72
73	/*
74	 *スムーズ変換スクリプト
75	  -------------------------------------------------*/
76	addEvent(window,"load",function(){
77		var anchors = document.getElementsByTagName("a");
78		for(var i = 0 ; i<anchors.length ; i++){
79			if(anchors[i].href.replace(/\#[a-zA-Z0-9]+/,"") == location.href.replace(/\#[a-zA-Z0-9]+/,"")){
80				anchors[i].rel = anchors[i].href;
81				anchors[i].href = "javascript:void(0)";
82				anchors[i].onclick=function(){SmoothScroll(this)}
83			}
84		}
85	});
86
87}