This paper presents SAM, a modular and extensible JavaScript framework for self-adapting menus on webpages. SAM allows control of two elementary aspects for adapting web menus: (1) the target policy, which assigns scores to menu items for adaptation, and (2) the adaptation style, which specifies how they are adapted on display. By decoupling them, SAM enables the exploration of different combinations independently. Several policies from literature are readily implemented, and paired with adaptation styles such as reordering and highlighting. The process - including user data logging - is local, offering privacy benefits and eliminating the need for server-side modifications. Researchers can use SAM to experiment adaptation policies and styles, and benchmark techniques in an ecological setting with real webpages. Practitioners can make websites self-adapting, and end-users can dynamically personalise typically static web menus.