I was reading through the docs and I guess I can do this if the user gives me "publish_stream" permissions.
Is there a Facebook Javascript API that makes the user like a page? Just as if they had clicked on a Like button.
It's not possible to like web pages, or Facebook pages through any API, except for very few approved apps.
You'll need to use a like button.
来源：https://stackoverflow.com/questions/9983296/how-can-i-use-the-facebook-javascript-api-to-automatically-make-a-user-like-a-pa