FormTools has very good documentation for Re-Captcha. But, in my opinion, Re-Captcha is complete rubbish:
1. It's absurdly difficult to decipher most of the time (why put your customers through that nonsense?)
2. Your customers are linking to Google every time they submit the captcha (why do that?)
3. Who really cares about "digitising" books?
There are far better captchas out there on the Web. One example is:
https://www.phpcaptcha.org/
Even better, is an example provided by William Steinmetz and Brian Ward in their book, "Wicked Cool PHP." The code can be downloaded from the publisher's Website:
http://www.nostarch.com/wcphp.htm
1. It's absurdly difficult to decipher most of the time (why put your customers through that nonsense?)
2. Your customers are linking to Google every time they submit the captcha (why do that?)
3. Who really cares about "digitising" books?
There are far better captchas out there on the Web. One example is:
https://www.phpcaptcha.org/
Even better, is an example provided by William Steinmetz and Brian Ward in their book, "Wicked Cool PHP." The code can be downloaded from the publisher's Website:
http://www.nostarch.com/wcphp.htm