I've got few requests to add WMP captcha to FBU, but I'm facing some issues.

When I check the captcha it stucks at 17% (when 768 target_hashes chosen) or at 50% (when 256 target_hashes chosen). Even after 5 mins it won't move. At the same time the hashes for that user in the WMP dashboard are above 2k.

When I click the checkbox the javascript console spits:
TypeError: captcha.on is not a function