//rollover
var RollOver = Class.create();
RollOver.prototype = {
initialize: function(option) {
  var props = { //外部から指定可能に
    hclass : "btn", //class=rolloverの要素が対象
    suffix : "_on" //オーバー画像はファイル名に_ovrが付いてること
  };
  if(option) for(var key in option) props[key] = option[key];
  $$('img.'+props.hclass,'input.'+props.hclass).each(
    function(el){
      var osrc = el.getAttribute('src');
      if (!osrc) return;
      var hsrc = osrc.replace(/(\.gif|\.jpg)/,props.suffix+'$1');
      (new Image()).src = hsrc; //キャッシュに読込む
      el.observe("mouseover",function(){
        el.setAttribute('src', hsrc);
      }).observe("mouseout",function(){
        el.setAttribute('src', osrc);
      });
    }
  );
}
}//prototype
Event.observe(window,'load',function(){new RollOver();});



//別ウィンドウでリンク
function externalLinks() {  
if (!document.getElementsByTagName) return;  
var anchors = document.getElementsByTagName("a");  
for (var i=0; i<anchors.length; i++) {  
var anchor = anchors[i];  
if (anchor.getAttribute("href") &&  
anchor.getAttribute("rel") == "external")  
anchor.target = "_blank";  
}  
}  
//window.onload=externalLinks;
Event.observe(window, 'load', externalLinks, false);