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

For convenience to inject (and indicate it's presense) jQuery in Chrome even into the HTTPS page with no-conflict mode to Prototype (indicates if Prototype is present on the page too) You probably would prefer jQuerify extension (jQuerify for Chrome) quality of which was proved by thousands of users during several years of experience. In one phrase: "Save your time".