It depends, I've met developers who considered everything above the database to be 'front-end' and front-end developers who consider their domain to end 'as far

It depends, I've met developers who considered everything above the database to be 'front-end' and front-end developers who consider their domain to end 'as far back as' the Service layer so I think the line is not so clear cut. On the otherhand, I consider myself a back-end dev who is happy writing from the Controllers back to SQL if necessary. I don't think in terms 'seriousness' but I firmly believe front-end UI work is a completely different skillset and is far more art than science. I would agree though that Javascript developers are not as respected as they should be.