An alternative to ReCAPTCHA for devices or browsers unable to support it

[lady_angelina]

Title
An alternative to ReCAPTCHA for devices or browsers unable to support it

Short, concise description of the idea
I would like to have an alternative method of "proving that a user is a human" to ReCAPTCHA for devices or browsers that are unable to support it.

Full description of the idea
Several functions of LiveJournal are contingent upon passing the ReCAPTCHA test. These include creating accounts and posting comments in some cases (especially when the journal owner has required it or when an entry has exceeded 5,000 comments). Unfortunately, some devices (especially mobile phones) and possibly certain older browsers are unable to support ReCAPTCHA, thus barring the user from performing these actions.

I have no clue as to what alternative there could be nor how to implement it. This is where you guys come in (hopefully the technically-minded) to discuss ideas and thoughts on this. ;)
An ordered list of benefits

• More usability for people who access LiveJournal via devices or browsers unable to support ReCAPTCHA.

An ordered list of problems/issues involved

• I haven't a clue as to whether this is even possible or how it would be implemented. It may be that this is entirely infeasible.
• If there is somehow a way to do this, then the usual time and trouble to code and implement it.

EDIT: I've just discovered that there is a non-JS version of the ReCAPTCHA dialogue (for lack of a better term), which produces a large string of code for you to copypasta into a text box. However, this seems to use frames, which my mobile browser does not support. The problem is that the dialogue does not appear at all, so I can't even do the audio test, etc.