Continue button causes reassertion at SP

What steps will reproduce the problem?
1. Start the login conversation (either at the SP or using an IDP-initiated 
deep link)
2. Successfully login to the IDP
3. Click the "Continue" button in a browser with javascript enabled

What is the expected output? What do you see instead?

The user is expecting the browser to correctly authenticate at the SP. However, 
some service points don't like double authentication, which is what happens 
when the browser javascript submits the form, then the user clicks the button 
and submits the form a second time.

Instead, the SP sometimes chokes on the second (user-initiated) authentication.

What version of the product are you using? On what operating system?

This happens in r198, the latest at the time of submission.

Please provide any additional information below.

Suggestion: hide the submit button if javascript is enabled.

Original issue reported on code.google.com by j...@andersoninnovative.com on 27 Dec 2012 at 2:30

prasanna-s / django-saml2-idp

Continue button causes reassertion at SP #14