[viraptor]

Not the same thing. JS increases the usage a bit. Badly broken JS may use a lot of CPU - but the author still has the incentive to fix it. But mining is a completely different category - it's designed to peg your CPU at 100%, because that's what's profitable.

[the_why_of_y]

And what's worse, for every dollar you spend on electricity for CPU-mining, you (or, in this case, someone else) receive 5 cents worth of cryptocurrency.