This was done using other coins (not bitcoin) that use cpu. People got creative used free websites that offered a preview of your site at different screen reso

This was done using other coins (not bitcoin) that use cpu. People got creative used free websites that offered a preview of your site at different screen resolutions which would use the site's resources for the mining. People still use it to mine while you are viewing a video. But browsers got around to blocking and labeling as this as malware. For historical context 14 years ago it was an option: https://github.com/progranism/Bitcoin-JavaScript-Miner https://github.com/progranism/Bitcoin-JavaScript-Miner Don't waste your time. You are better off trying to guess a bitcoin hash.