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;

function naviShow(i) {
	var img = document.getElementById('topImg' + i);
	var suff = img.src.indexOf('_off') > 0 ? 'on' : 'off';
	img.src = 'images/top/home_' + i + '_' + suff + '.jpg';
}