I am the web developer for I Said Sit!. We have had an ongoing problem with our registration page at: http://isaidsit.com/index.php/registerform
We are having a major problem that I hope you can help with. I have had 4 programmers look at the problem and cannot find where there is an issue. We have installed the site on our test sever and we cannot duplicate the process. I installed it on my personal server and we didn't get the errors, it worked fine in all the browsers on several different traditional and mobile devices.
On the following page we have a big registration form that will not work in Safari on a computer. We can use the form on an iPad or and iPhone or PC using Safari without any problems, if it's used on a Mac computer we get several different errors:
Those are the most often reported problems.
Tested OK on an iMac running MacOS 10.6.7 and Safari 5.0.5. (Abandoned at the Credit Card Payment step.)
The markup, as mentioned by @David Thomas, is atrocious - 91 errors from the W3C Validator, and a quick visual inspection shows what looks like another complete HTML page being loaded into the body of the HTML page.
Some general feedback on the form (feel free to ignore this if you want):