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 = '';
}
function hideIndexElement(elementId, iBot, iTop) {
    for (var x = 2; x <= iTop; x++) {
        showElement(elementId+x);
    }  
    for (var x = iBot+2; x <= iTop; x++) {
        hideElement(elementId+x);
    }  
}