function rollOver(){
	//マウスオーバーさせるimgのファイル名の一部（必須）
	var defalt_name="_off.";
	
	//マウスオーバー時に上記で指定した箇所を置き換える文字（必須）
	var over_name="_on.";
	
	if(document.getElementsByTagName){
		if(defalt_name == "" || over_name == ""){
			alert("error function swap_img()");
		}
		
		var images = document.getElementsByTagName("img");
		var preloadimg=new Array();
		
		for(var i=0; i<images.length; i++){
			if(images[i].className == "rollover"){
				var src = images[i].getAttribute("src");
				var fType =  src.substring(src.lastIndexOf('.'), src.length);
				var overImage = src.replace(fType,"_s" + fType);
				
				
				preloadimg[i]=new Image();
				preloadimg[i].src=overImage;
				
				images[i].onmouseover=function(){
					var src = this.getAttribute("src");
					var fType = src.substring(src.lastIndexOf('.'), src.length);
					var reg = new RegExp("_s" + fType);
					if(!src.match(reg)){
						this.setAttribute("src",this.getAttribute("src").replace(fType,"_s" + fType));
					}
				}
				images[i].onmouseout=function(){
					var src = this.getAttribute("src");
					var fType = src.substring(src.lastIndexOf('.'), src.length);
					this.setAttribute("src",this.getAttribute("src").replace("_s" + fType,fType));
				}
				if (navigator.userAgent.indexOf("Firefox") > -1) {
					var pa = images[i].parentNode;
					var parentTag = pa.tagName;
					if(parentTag.match(/a/i)){
						pa.onmouseup = function(){
							var ee = this.getElementsByTagName("img");
							for(var i=0; i<ee.length; i++){
								if(ee[i].className == "rollover"){
									var src = ee[i].getAttribute("src");
									var fType = src.substring(src.lastIndexOf('.'), src.length);
									var reg = new RegExp("_s" + fType);
									if(ee[i].src.match(reg)){
										ee[i].setAttribute("src",ee[i].getAttribute("src").replace("_s" + fType,fType));
										return true;
									}
								}
							}
						};
					}
				}
			}
		}
	}

}
//function default javascripts
onload = function() {
	if (!document.getElementById) return
	rollOver();
}