access masterpae control from other page.

Hi. i hava a masterpage and an default.aspx page that derives from masterpage. On default.apsx, i list products. when i click add basket buton that product is added to shoppingbasket. i do this using jquery. On mastepage,there is a label that shows how many product is in shopping basket.
i want to do this. when i click add basket on default.aspx, label control on masterpage show the new product count on shoppingbasket.How can i access masterpage control and change using javascript/jquery from default.aspx.Thanks.