//external.js
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を上書きせず追加する関数_091101
function addEvent(elm,listener,fn){
	try{
		elm.addEventListener(listener,fn,false);
	}catch(e){
		elm.attachEvent("on"+listener,fn);
	}
}

window.onload=externalLinks;