jehan / Dominos Pizza Voucher Codes

Hi there, I'm having some issues getting the pop up to appear. When I click the Ninja Turtle icon, nothing happens.
I'm using Chrome v50.0.2661.102 m, Windows 8.1 and Tampermonkey v4.0.25. I checked the console for any output that appears, all that happens is that each time I click the Turtle button, this appears:

CTFM highlighted text sent:

Any help would be greatly appreciated, thanks!

EDIT: Tried with the latest versions of Firefox and Greasemonkey and it wouldn't let me actually install the script because https://raw.githubusercontent.com/kvz/phpjs/master/functions/strings/sha1.js is down. I tried replacing that dependency with what seems to be the one at https://raw.githubusercontent.com/kvz/locutus/master/src/php/strings/sha1.js but that makes the Turtle icon stop appearing altogether (it reappears when I change it back). I also found this, which may or may not be relevant http://locutus.io/2016/04/breaking-bc/

Sounds like the author of the SHA1.js script made changes to his project which broke backwards compatibility? I dunno, I'm not a dev. Hopefully this helps!

DOUBLE EDIT: Works in Firefox now! Replaced the old https://raw.githubusercontent.com/kvz/phpjs/master/functions/strings/sha1.js dependency with the legacy version of the script at https://raw.githubusercontent.com/kvz/locutus/v1.3.2/functions/strings/sha1.js

Weirdly this doesn't make it work on Chrome, just on Firefox.