function checkRadio(class_name)
{
    $('.'+class_name).attr('checked', true);
    $('a.corso').removeClass('selected');
    $('a.'+class_name).addClass('selected');
    return false;
}

function block_field(class_name)
{
    $('.'+class_name).attr('disabled', true);
    return false;
}

function unblock_field(class_name)
{
    $('.'+class_name).attr('disabled', false);
    return false;
}

function show_div(class_name)
{
    $('.'+class_name).show();
}

function hide_div(class_name)
{
    $('.'+class_name).hide();
}