The registration form uses HTML5 input field awesomeness. This makes things happen automatically – such as the pop-up calendar for dates, format verification for things like telephone numbers and email addresses. Unfortunately, not all browsers support HTML5, such as older versions of Internet Explorer and all versions of Mozilla Firefox. I’ve added input checking for the date of birth field to verify that for those browsers, the date is being entered as MM/DD/YYYY or YYYY-MM-DD or MM/DD/YY.
Also, unrelated, I cleaned up the processing fee box a bit.