anyone here good at java script? i need a bit of code knocked up to replicate some "add to basket" style code.

basicly the user puts a buy button on thier site, and the reference to the script hosted on my site. the buy button contains an id for a product. when clicked, that would store the id as a cookie, and pops up a confirm page.

thats basicly it. then when the click the "finish shopping" href on their site, itll take them to me and i read the ids from the cookie and generate the checkout page.

can anyone help and how much?