function safeLinkTarget()
{
    var links = document.getElementsByTagName('a');
    
    for (var i = 0; i < links.length; i++) {
        if (links[i].rel=='_blank') {
            //links[i].target = '_blank';
            links[i].setAttribute('onclick', 'window.open("'+links[i].href+'", "_blank"); return false;');
        }
    }
}

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