How to run jQuery directly on any page in the browser?

Question

Is there some programmatic way (or maybe a browser plugin) that allows users to arbitrarily run any jQuery they want on a webpage that is currently loaded in their browser?

Answer 1

FireQuery is a great Firebug extension that can include jQuery for you and from there you´re able to use jQuery in your console.

"jQuerify: enables you to inject jQuery into any web page"