//Functions to run on page load
var Site = {
	start: function() {
	    ExternalLinks.start();
    }
};

//XHTML compliant way of doing _blank
var ExternalLinks = {
    start: function() {
        if (!document.getElementsByTagName) return;
        var anchors = document.getElementsByTagName('a');
        for (var i=0; i<anchors.length; i++) {
            var anchor = anchors[i];
            try {
            if (anchor.getAttribute('href') && anchor.getAttribute('rel') == 'external')
                anchor.target = '_blank';
            }catch(err) {}
        }
    }
};

Event.observe(window, "load", Site.start);