MemriseForgiveTypos.user.js

Shows an alert box once if the Levenshtein distance of a given answer and the correct answer is 1 or 2.

I'm not a big fan of making a hack like this but at the same time I don't think you should be punished for accidental typos as Memrise currently does. Use at your own peril.

Installation

I have tested the userscript on Chrome and Firefox using Greasemonkey.

Chrome

Method 1 (Easier and recommended)

1. Install Tampermonkey extension on Chrome Store.
2. Open MemriseForgiveTypos.user.js and click Install.

Method 2

1. Download MemriseForgiveTypos.user.js to your computer.
2. Go to the extension view in Chrome (chrome://extensions).
3. Drag the MemriseForgiveTypos.user.js file on the extension page. It should say "Drop to install" as you do so.

Firefox

1. Install Greasemonkey.
2. Open MemriseForgiveTypos.user.js and click Install.

Safari

I haven't tried. Search Google for ways to install userscripts.