Can't use nocaptcha recaptcha in China, load callback to fallback?

Hi all, I am writing an application for the client, the user will be occasionally access in China network. As a result, reCaptcha is not working there. Are there any way that the "onloadCallback" can check when the loading is fail to and I may fallback to another authentication method? Any idea is much appreciated! Thanks Wayne -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://bit.ly/1dkFnYd. For more options, visit http://bit.ly/P65DvS.