The requires more steps and a slower process. User-agent is a one step process. Browser capabilities means returning something back to the browser and potentially coming back to the server.
While it has obviously been abused, neither way is ideal. There's no way for a server to say "tell me the browser capabilities before I serve you the request".
While it has obviously been abused, neither way is ideal. There's no way for a server to say "tell me the browser capabilities before I serve you the request".