Event.observe(window, 'load', init_extern_links);

function init_extern_links(event) {
	var links = $A(document.getElementsByTagName('A'));

	links.each( function (link) {
		if( Element.hasClassName(link, 'external_nodecor') 
		&& link.href.indexOf('alexa.com') < 0 
		&& link.href != '' 
		&& link.href != '#' 
		&& link.href.indexOf('javascript') < 0 
		&& link.href.indexOf('mailto') < 0 ) 
		{
			Element.addClassName(link, 'external_link');
			link.title = 'Link to ' + link.href;
		}
	});
}