Enable JavaScript in URL bar in Firefox

Is there any method in about:config to enable in the URL bar JavaScript prefixed by javascript: to run in Firefox?

browser.urlbar.filter.javascript: false doesn't seem to work.

2 Answers

browser.urlbar.filter.javascript: false doesn't seem to work.

Indeed it doesn't. You can work around it using Bookmarks (at least until Mozilla block that as well):

• Set up a Bookmark with the location: javascript:%s

• Set the keyword for that bookmark as: javascript

Now you can run JavaScript from the address bar in the format: javascript alert('Hello World') which is very similar to the old javascript:alert('Hello World') method - it's just that the colon needs to be replaced by a space.

Source Executing JavaScript in Firefox address bar - AutoHotkey Community

The setting you are trying to use only controls whether javascript: URLs show up as auto completes when you type in the URL Bar. From

True
Filter out “javascript:” URLs from appearing in the Location Bar autocomplete dropdown. (Default)

False
Allow “javascript:” URLs to appear in the dropdown.

It seems javascript: URLs are completely disabled in newer version of firefox.

However you should still be able to save javascript: URLs as bookmarks and activate them by clicking on them.

Other people have noticed this too: