You can use ajax for accessing a server side script for checking availability of email and then showing some notification/error message depending upon the response you get from server.
What you can do is go check the availability of the username through an jQuery http call when the user has finished typing something the email field (onblur). If its not available, you might want to give him or her a visual indication (for example, turn the field red) to prompt another email.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.