function addEvent( obj, type, fn ) {
  if ( obj.attachEvent ) {
    obj['e'+type+fn] = fn;
    obj[type+fn] = function(){obj['e'+type+fn]( window.event );}
    obj.attachEvent( 'on'+type, obj[type+fn] );
  } else
    obj.addEventListener( type, fn, false );
}

function removeEvent( obj, type, fn ) {
  if ( obj.detachEvent ) {
    obj.detachEvent( 'on'+type, obj[type+fn] );
    obj[type+fn] = null;
  } else
    obj.removeEventListener( type, fn, false );
}

function openExternal(link) {
	window.open(link, "_blank");
	return false;
}

function checkForExternalLinks() {
	if ( document.getElementsByTagName ) {
		links=document.getElementsByTagName("a");
		for (i=0; i < links.length; i++) {
			if ( links[i].className.search("external") != -1 ) {
				links[i].onclick=function() { return openExternal(this); }
			}
		}
	}
}

addEvent(window, 'load', checkForExternalLinks);