There is a spreading tendency nowadays that miners are minig cryptocurrency on users CPU by the owners of websites, and the most famous browsers aspire to release special extensions in order to prevent that. Opera browser the first one that is launching NoCoin, a cryptocurrency mining protection, which keeps miners away by blocking mining scripts.
Opera cryptocurrecy mining protection
NoCoin will provide users with safe and reliable way to block miners from using their CPU and power without their consent. Moreover, NoCoin is also open source and licensed under MIT.
Currently NoCoin is in development but available in Opera 50 Beta RC, ans the full version of Opera 50 is stated to be released in January 2018.