There are two parties that could be responsible for determining whattype of content you are getting in a HTTP response, whether the data isHTML or a PDF or a JPEG or so on: the server or the client. The web hasopted to make it determined by the server ,and this is the correct place for a simple reason: consistency .

Imagine a world where the clients determine what the content type is.If there is no standard for how clients determine the content type, theconsistency problems are obvious;