Now some people are ok with this form of revenue for websites as long as they are aware it is going on. So say a choice between seeing ads or running the miner. Many others are completely against the idea as heavy browsing could slow down their computer and have an impact on electricity bills.
According to a report by ArsTechnica there could be a least 2500 websites out there running embedded crypto-currency miners that are hidden from users. Independent cybersecurity researcher, Willem de Groot told Ars that he estimates JS miners may have proliferated to 2496 websites, and its adoption is on the rise. Coinhive seems to be in the middle of the controversy as they sell easy-to-integrate crypto-currency miners that can be embedded into websites as a source of revenue.
As of writing neither Google or Mozilla have come up with any type of anti-miner blocking or warnings in their browsers. The Ad Block Plus browser extension has introduced a feature that disables scripts that exhibit this type of behavior. Anti-virus software vendors like McAfee and Kaspersky have set out to identify and block sites with embedded miners.