If you aim at Webdevelopement as a whole, then it doesn't matter because you will need both(:
and PHP is for Back End Developement ( Server )
For the people that disliked my answer because I said he needs PHP:
It's like saying "buy a boat" when asking "Should I buy a car or a motorcycle first?"
- PHP ( For combining all courses)
You can always learn a language for back-end later if you want. :)
But Php can do some pretty awesome things, so it's really up to you.