function setupPreferedItems () {
    url = '/json/prefer.php';
    new Ajax.Request(url,
                     { method: 'get', onComplete: displayPreferedItems });
}

function displayPreferedItems (request) {
    eval('var results = ' + request.responseText);
    var html = '';

    for (var i = 0; i < results.length; i++) {
         html = html
              + '<li>'
              + results[i]
              + '</li>';
    }
    $('prefered-items').innerHTML = '<ol>' + html + '</ol>';
}