PHP is certainly not dead. I'm still making a living writing it. ;-)
Javascript is a good way to go if you want to build front end web apps and sites.
For most of those site, they will need to talk to a server somewhere, so it's still good to know how to write server-side code. there are a lot of places that still use PHP, so it is a language that may come in handy.

Whatever server side language you learn, you do need to learn one if you are going to build fun stuff. Javascript can only do so much, and then it needs a hand from something like PHP.

I'd also recommend learning about database design and development. You may not be building the database, but if you know how it works, that makes it much easier to model data at the front end.

I startd my life as a Java programmer, then moved to PHP doing mostly back end builds (PHP and MySQL). Now I'm mostly front end. But the things I learned from back end coding are very relevant and useful to me now.

So learn as much as you can about stuff you are interested in, and don't get too hung up on which language is the best. At the end of the day, the one that pays the bills, is the best language.