function remove_fields(link)
{
    $(link).prev("input[type=hidden]").val("1");
    $(link).closest(".fields").hide();
}

function add_fields(link, association, content)
{
    var new_id = new Date().getTime();
    var regexp = new RegExp("new_" + association, "g");
    $(link).parent().before(content.replace(regexp, new_id));
}