I have a javascript quiz plugin (created by a third party) which works well but has a Facebook Share button which is obsolete and no longer works.

I want to add a Facebook Like button to the final page of the quiz and ideally I'd like it to display the user's score when it appears as an update on their newsfeed/timeline in Facebook.

Any tips on how I can do this? I have added Facebook Like buttons to websites in the past but I'm a javascript novice.