I'm having to guess at the context of your question... You can use the Web Console to run scripts in the context of the page, so if you have a script you want to test -- to generate a background post from data in the page or anything else -- you can paste and execute it there. https://developer.mozilla.org/docs/Tools/Web_Console If you have something else in mind that isn't answered on MDN, there is a forum for developer tools over here: https://discourse.mozilla.org/c/devtools