There was a mistake in the Javascript credit card generator, meaning it would not work on MS Internet Explorer or Opera. This has now been fixed, and I have tested it successfully on:

• Firefox 1.0.6
• Konqueror 3.4.1
• Internet Explorer 6.0
• Opera 8.5.2

The archive now also includes an example on how to use the Javascript version (which seems the most popular).

Get it here