That's interesting, I've never heard about cryptojacking until now. But I don't think a laptop would have enough power to mine. It wouldn't even generate enough coins to be worth the effort of hacking into your machine.
How did you know that it was jacked? Did you see a process running excessively in the background? And you said by adding nocoin to your browser it stopped, so was it being run as a script?
Cryptojacking is actually pretty common. They tend to mine Monero, because that still gives them rewards if it's done on a very large scale.
The people who are running the malware could have up to 100k slave computers in their network, generating them thousands of dollars per day/week.
It's usually pretty easy to notice too, when your CPU goes through the roof.
Running noscript is also a solution btw.