
Toggle the document.designMode property on your web page to control whether the entire document is editable.
This extension works in Safari and Chromium-based browsers.
Ensure that the active application is either Safari, Google Chrome, or a Chromium-based browser window.

For this extension to work, you need to enable the following option:
Pro tip: Assign a hotkey for the "Toggle Design Mode" command.
Toggles the document.designMode property on your web page to control whether the entire document is editable.
Release of the Web Page Design Mode extension