How can I stop websites running an integrated Bitcoin miner without disabling javascript altogether? "Bitcoin Plus" is one example of a javascript bitcoin mining client that can CPU mine bitcoins through a browser when viewing a website. Here is a screenshot from 4bitcoins dot com which automatically starts the miner when you load the page:


It could be considered a form of theft for a website to profit from the extra electricity used by a viewer of the page, and definitely isn't environmentally friendly as CPU mining through javascript is hugely inefficient and any revenue earned doesn't even come close to covering the cost of the electricity consumed (and besides, in this case the benefit is to the website, and the cost is to the user). 

Doing some quick maths I'd estimate that the mining would earn the website owner around 0.12 US cents per 24hrs running, at a cost of around 17 cents to the user in power (assumed 1BTC=$5US, difficulty around 1.8m, power 14c/kWh). 

In short, it's desirable to block such functionality from running without the user's consent.

How could such integrated mining be disabled without blanket-disabling javascript on all websites? Bear in mind that even though the miner is visible on 4bitcoins dot com, it doesn't need to be visible to work.

ps: I didn't use standard syntax for the website name, as that will only encourage search engines to send more traffic there!
You can use Adblock Plus to block the miner script.  In this case it would be:

http://www.bitcoinplus.com/js/miner.js