The HTML rendered for non-JavaScript and JavaScript users is different. it's okay to use enhancements but they should be at least positioned correctly.
The way I tend to explain this is a problem is using the following scenario. You ring your grandfather and try to help him register for an account. You tell him there is a captcha he needs to fill above the create account button as you see this:
He might have a bad connection/browser though that we don't load JavaScript on so he sees this:
Let's make sure the initial HTML appears in the correct place.
This also blocks a mobile web card T74910

