How to install
Mac (Safari): show the Favorites bar (View › Show Favorites Bar), then drag the Speed Read button above onto it. With iCloud Safari sync on, it also appears on your iPhone and iPad.
iPhone / iPad: tap Copy bookmarklet code. Bookmark any page (Share › Add Bookmark, name it “Speed Read”). Then open Bookmarks, tap Edit, select the new bookmark, and replace its address with the copied code.
Using it: open an article in Safari, open Bookmarks, and tap Speed Read. The reader opens in a new tab with the article loaded.