An interactive signup / register form designed by Riccardo Pasianotto. You are asked to enter your email and on submitting that the field changes to one that asks you to enter your password and then finally it will ask you to resubmit your password. One potential issue with this is that there is no way for the user to go back and edit their response.
If you are having trouble with the pen, try the archived copy on GitHub
Single Field Signup Form Snippet
See the Pen Interactive Sign Up Form by Riccardo Pasianotto (@rkpasia) on CodePen.0