My initial question was "What determines if a page can or can't be displayed in Reader View in Firefox?" but I found the answer on a Webmasters StackExchange question here.
As far as I understand, sites that don't automatically show the option to enable Reader View have a problem with their code/tag/html/something.
The Firefox support page for Reader View (here) suggests something similar: "If a page is available in Reader View, the Reader View icon will appear in the address bar".
My question now is, if Reader View icon doesn't appear,
Is there a way to force enable Reader View on such pages?
Visited this discussion on Reddit but it doesn't answer my question.
I considered posting this question in Software Recommendations but I'm not sure an addon will provide a solution. Maybe this can be done with a script or a Firefox setting in about:config or something else entirely?
Best Answer
Solution 1: The Best One
You can try installing Activate Reader View, an add-on for Firefox that will force reader view even if the icon is not displayed.
This add-on adds a button to the toolbar. Clicking on it will (force) activate Reader View even if the icon in the address bar is not present.
Technically this Add-on prepends "about:reader?url=" to the current tab's address.
Solution 2: Manual
Use Reader View on any site/webpage by adding below prefix to the url in the address bar:
For example, to view
https://example.com/page1.htmlin Reader View,enter
about:reader?url=https://example.com/page1.htmlin the address bar and proceed.Note: Doesn't work always.
Solution 3: For older version of Firefox
Install Pentadactyl add-on for firefox and create a custom command:
And then you type
:readerto get the Reader View.You can also map a keyboard shortcut to your custom command like so...
A simple Ctrl + R will force Reader View.
Note: Pentadactyl is (probably) no longer in development. Last release was in March 15, 2014 and works with Firefox 24.0 - 31.*