function toggle_display (element_id) {
    var element = document.getElementById(element_id)
    var style = element.style;
    if (style.display == 'none') {
        switch (element.nodeName) {
        case "DIV":
        case "P":
        case "TABLE":
            style.display = 'block';
            break;
        case "SPAN":
        case "I":
        case "B":
            style.display = 'inline';
            break;
        }
    } else {
        style.display = 'none';
    }
    return false;
}