After a bunch of testing I figured out what was causing the problem. The websites where I encountered the error were those that were set up on https servers (with SSL).
In the article in ASP Snippets where I got the code there is a section called RECaptcha Client Side Implementation and Validation. The first line of code is a JavaScript link that has the following URL:
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
In an old article about reCAPTCHA 1 I learned that SSL sites need to have https links for these scripts. So I changed this one line of code in one of my SSL sites to this:
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
The only difference between these two lines is that the src for the second one begins with "https:" When I made this one simple change, the reCAPTCHA routine worked perfectly in all of the sites where the domains are on https servers.
A big thank you to Mudassar Ahmed Khan for the original code. His contributions in the ASP Snippets website are the best!
