Browser Plugin: Readable

That function exist by default in all major browser. In firefox it's called "reader view".

In chrome you have to visit chrome://flags/#enable-reader-mode then Enable the option “Enable Reader Mode.” Click the “Relaunch” button that appears at the bottom to relaunch Google Chrome. Now you can visit any website or webpage with long readable text. Click on the book icon on the right of the address bar to enable reader mode.