function setupCounter () {
    url = '/json/counter.php';
    new Ajax.Request(url,
                     { method: 'get', onComplete: displayCounter });
}

function displayCounter (request) {
    eval('var results = ' + request.responseText);
    $('counter-total').innerHTML = results['total'];
    $('counter-today').innerHTML = results['today'];
    $('counter-yesterday').innerHTML = results['yesterday'];
}