SnezhanaLast,
смотрите код выше - нужна строка a = a.join(",");
ADDRESS: a

SnezhanaLast,
бред какой-то ...

var a = $.map($('user_street, .user_home, .user_acces, .user_apartment'), function(el) {
    return el.value
});
a = a.join(",");
$.ajax({
    type: 'POST',
    url: '/iconthandlers/order.php?t=' + new Date().getTime(),
    dataType: 'json',
    data: {
        PHONE: $('.order_form_fields .phone').val(),
        NAME: $('.user_name').val(),
        DELIVERY_NAME: $('.delivery_list option:selected').text(),
        ORDER_EMAIL: $('.order_email').val(),
        DISTRICT: $('.delivery_list').val(),
        ORDER_STATUS_ID: 'new',
        PROMOCODE: $('.promo_value').val(),
        PAY_SYS: payment_id,
        PAY_SYS_TEXT: payment_text,
        DELIVERY_PRICE: $('.delivery_price_value').text(),
        PERSONS: $('.persons').val(),
        CHANGE: $('.need_short_change').val(),
        ONLINE_PAY_STATUS: ops,
        ADDRESS: a
    },
    success: function(order_id) {
        $('.out_sum').val($('.cart_btn span').text().split(' ').join(''));
        $.cookie('order_id', order_id, {
            path: '/'
        });
        $('.cart_btn').find('span').text('').parent().removeClass('cart_full').addClass('cart').html("");
        renderGiftScale(0);
        refreshGifts(0);
        refreshGiftsInCart(0);
        var scrollTop = window.pageYOffset || document.documentElement.scrollTop;
        var goods = new Array();

    }
})

рони, Большое Вам спасибо! Код отлично работает. :)