jQuery ajax JSON到php

Question

I hope you can help. I have the following js code:

if ((width >= 360) && (width <= 2400) && (drop >= 360) && (drop <= 2400)){
            $.post("file.php",{
                change: change, 
                width: width, 
                drop: drop, 
                typeselect: typeselect, 
                colour: colour,
                variations: vari
            },function(data){
                var info = jQuery.parseJSON(data);

vari in firebug comes back as

[{"variation_id":"1110","attributes":{"attribute_colour":"chocolate","attribute_type":"tape-38mm"},"image_title":"wooden-chocolate-tape","image_alt":"","price_html":"<span class=\"price\"><span class=\"amount\">£36.00<\/span><\/span>","availability_html":"","sku":"","weight":" kg","dimensions":"","min_qty":1,"max_qty":0,"backorders_allowed":false,"is_in_stock":true,"is_downloadable":false}]

For some reason it isn't posting anything for variations. Firebug says the POST is:

change  drop
colour  
drop    360
typeselect  
width   360

I'm assuming the vari is in JSON format.

Any help would be great. Thanks Mark