https://www.ryotanji.com/imgover.js

1//ƒXƒNƒ[ƒ‹
2function gotoTop() {
3  var IE  = navigator.appName.indexOf("Microsoft Internet Explorer",0) != -1;
4  if( IE ){
5    position = document.body.scrollTop;
6  } else {
7    position = window.pageYOffset;
8  }
9  movePosition();
10}
11
12function movePosition() {
13  position = Math.floor(position*0.8);
14  if( position > 0.1 ){
15    window.scrollTo(0,position)
16    setTimeout("gotoTop()",30);
17  } else {
18    window.scrollTo(0,0);
19  }
20}
21
22//ƒRƒs[ƒ‰ƒCƒg
23function Year(){
24now=new Date();
25if(now.getYear()>=2000){document.write(now.getYear())}
26else{document.write(now.getYear()+1900)};
27}
28
29//ƒCƒ[ƒWƒ[ƒ‹ƒI[ƒo[
30//<img src="aaa.jpg" alt="" class="imgover" />
31function initRollovers() {
32	if (!document.getElementById) return
33	
34	var aPreLoad = new Array();
35	var sTempSrc;
36	var aImages = document.getElementsByTagName('img');
37
38	for (var i = 0; i < aImages.length; i++) {		
39		if (aImages[i].className == 'imgover') {
40			var src = aImages[i].getAttribute('src');
41			var ftype = src.substring(src.lastIndexOf('.'), src.length);
42			var hsrc = src.replace(ftype, '_o'+ftype);
43
44			aImages[i].setAttribute('hsrc', hsrc);
45			
46			aPreLoad[i] = new Image();
47			aPreLoad[i].src = hsrc;
48			
49			aImages[i].onmouseover = function() {
50				sTempSrc = this.getAttribute('src');
51				this.setAttribute('src', this.getAttribute('hsrc'));
52			}	
53			
54			aImages[i].onmouseout = function() {
55				if (!sTempSrc) sTempSrc = this.getAttribute('src').replace('_o'+ftype, ftype);
56				this.setAttribute('src', sTempSrc);
57			}
58		}
59	}
60}