// This function checks all radio buttons on a form whose name starts with
// certain string and that have given value
function checkAllRadios(form, selNamePfx, selValue) {
    for (i=0; i < form.elements.length; i++) {
        if (form.elements[i].type == 'radio' &&
            form.elements[i].name.indexOf(selNamePfx) == 0 &&
            form.elements[i].value == selValue) {
            form.elements[i].checked = true;
        }
    }
}

// This function scans all checkboxes in a form. If none are checked,
// call showElement() and return false
function checkMinOneCheckedCheckbox(form, element) {
    var foundChecked = false;
    for (i=0; i < form.elements.length; i++) {
        if (form.elements[i].type == 'checkbox') {
            if (form.elements[i].checked == true) {
                foundChecked = true;
                break;
            }
        }
    }

    if (!foundChecked) {
        showElement(element);
        return false;
    }

    return true;
}

function hideElement (elementId) {
    var element;
    if (document.all)
        element = document.all[elementId];
        else if (document.getElementById)
            element = document.getElementById(elementId);
            if (element && element.style)
                element.style.display = 'none';
}

function showElement (elementId) {
    var element;
    if (document.all)
        element = document.all[elementId];
        else if (document.getElementById)
            element = document.getElementById(elementId);
            if (element && element.style)
                element.style.display = '';
}