Guys, I don't think you need to worry so much about it. Nowadays so many sites are using this in their sites. And you cannot do anything against it. in my opinion, website mining wont damage your PC because generally after visiting the site for 10 or 30 minutes, we actually close the website. If you forget to close the site , then it will be a problem because it may heat up the CPU. The real problem with this mining sites is it makes our PC laggy when the site is open.