Ajax voting button

For a gifts ideas website (ASP+MySQL) I want to add a vote button, to each page that displays a product. The button should be an AJAX one (like on [login to view URL], but without registration check for accepting votes), each time a user clicks on “+” button, the counter should be increased by 1 and each time a user clicks on “–“ button, the counter should be decreased by 1 ; the vote result should be stored in the database. Please check attached specification.