function map_pop_up() {
    var as = document.getElementsByTagName('a');
    for (i = 0; i < as.length; i++) {
        if (as[i].getAttribute('href').indexOf('/directory/map/center/') != -1) {
            as[i].onclick = function() {
                window.open(this.href, 'map_center', 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,width=600,height=400');
                return false;
            }
        }
    }    
}