This extension allows you to edit things on the current page for prototyping.
This makes it very easy to edit the current tab you are on, for screenshots or rapid prototyping. Just click the extension icon in the browser, make your edits directly on the page (you can even edit links!), then click it again to re-enable the page functionality/links.
Feel free to find the extension source here on GitHub: https://github.com/bluetidepro/Edit-ALL-THE-THINGS