Client-side only user’s FaceBook email without typing

Facebook allows you to get a users email without the user of your web site having to type (assuming the user of you site has a FB account).
You will first have to create a FB app to get your own FB app id here:

Here is the full working example of no back end FB user’s email:

Notice the call:

Here is a full video:
Let me know if you have problems reproducing this at