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Recaptcha is a clever way to keep the SPAM bots at bay. It forces the visitor to type in a couple of random words before the visitor can submit a POST to your site. Recaptcha accomplishes a secondary task, it digitizes books.
The words you see are scanned from books, and by using humans to identify and digitize the scanned words, it combines digital processing with distributed soft processors, the human brain.
The idea is ingenious. And although there are ways to defeat the system using a script, (OCR), it has a really good track record. Recently there has been some buzz about hackers being able to defeat recaptcha so Google upgraded recaptcha to make it slightly harder for OCR software to read the captcha.
Recently on a project I was looking through recaptcha documentation when I found a little bit of complaint from confused recaptcha users. In the documentation, Google suggested:
Recaptcha.create("your_public_key",
"element_id",
{
theme: "red",
callback: Recaptcha.focus_response_field
}
);
The callback sets the focus to the recaptcha response field. If you use Google’s code on a page where the captcha is displayed at the bottom of the page and the page is very tall, setting the focus has the undesirable effet of scrolling the page to the bottom.
To prevent your page from jumping, simply remove the callback property from the object and dont forget to remove the comma from the previous line.
