People tried this in 2013 or so, there's no point to it. Doing proof of work in javascript in a browser is so crushingly, pointlessly slow that there's no value at all. Some browsers also intentionally detect attempts to do proof of work and attempt to block it entirely.

▲ RobotToaster 4 hours ago | parent [-]

> Some browsers also intentionally detect attempts to do proof of work and attempt to block it entirely.

Then they'd be blocking themselves from the website.

▲ drum55 4 hours ago | parent [-]

https://blog.mozilla.org/en/firefox/block-cryptominers-with-...

    To help you combat these unwelcome scripts, we’ve partnered with Disconnect and compiled lists of domains that serve cryptomining scripts so you can block them directly through Firefox. When you download Firefox,  tracking protection is enabled by default, blocking known cryptominers.