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fascr (For a site called Reason) is a Firefox extension with functionality similar to brymck's excellent Chrome extension reasonable. It is not a port.

Current features

  • Block and "mute" users Posts by blocked posters and replies to them will disappear completely, as if they had never existed. Posts by muted posters, in contrast, will have only their content hidden (with option to temporarily display), with byline and reply preserved.
  • "Toggle" top-level threads When a conversation does not interest you, you can hide a thread by clicking "toggle" next to a top-level post. This will persist across refreshes without affecting other posts by that user.
  • Highlight posts by a certain user (e.g., you)
  • Navigate with hotkeys Press shift-alt-j to move forward through unread posts, shift-alt-k to move back
  • Count characters typed Note that it is actually bytes that are counted, because it appears that this is what Reason's limit is actually based on.

New in 0.7.xx

  • HTML tag buttons Common HTML tags can be inserted via buttons above comment boxes. If text is highlighted, the tags will surround the highlighted text; otherwise, an empty pair of tags will be placed at the current cursor position.
  • Inline alt text alt and/or title attributes are displayed as / concatenated to image captions, where applicable. Especially useful on mobile.
  • Optional 'mark-read-on-advance' mode See below for a more detailed description

Mark-read-on-advance Mode

The "classic" behavior of fascr and its Chrome equivalent reasonable is to treat all comments as unread when an article is first viewed, and thereafter, to mark them as read upon its next viewing. This is still the default behavior, and logical for most Android devices, which usually lack keyboards.

This behavior is straightforward and easy to implement, but irritating if you would like reply to a comment midway through reviewing the unread comments.

I have implemented a new behavior which can be enabled by selecting "Mark individual post as read when reached via hotkey" as the value of the option "Unread post tracking behavior".

With this option enabled, posts made after the first time you view an article will not be marked as read until you either reach them via hotkeys (as a reminder, shift-alt-j to move forwards and shift-alt-k to move backwards) or mark all as read at once using shift-alt-m -- even if you comment or refresh.

This way, you will never "lose your place" by making a comment.


  • Starting with 0.6.xx, fascr requires Firefox 34 or higher.

Mobile support

fascr is now built to work on Firefox for Android. It also almost certainly will not work on the forthcoming Firefox for iOS, which will probably not support extensions.

Usage notes / tips

  • Performance will be much better with an ad-blocking mechanism in place. Please donate to them instead.
  • Hotkeys will not work until the page is completely loaded.
  • To remove users from your blocklist, click on your username to the right of the Reason logo where is says "You are currently logged in as:". fascr will insert lists of all currently blocked and muted posters on that page; click on them to remove them.

Known issues

  • If a thread is toggled, clicking "Block" adds its poster to the blocklist, but does not remove the post. Un-toggling the thread rectifies the issue.
  • Hotkeys sometimes don't work. This appears to be a Firefox Add-ons SDK bug.



  • Download the XPI file
  • File -> Open (or CTRL-O) the file
  • Click "Install"

Mobile (Android)

  • Download the XPI file
  • Click the "Download completed" message in the notification tray
  • Click "Allow"
  • Click "Install"


The extension itself is distributed under the MIT license. Font Awesome is licensed under the MIT license and the OFL 1.1.

Contact me