Simple Email And Phone Number Validation From Form

I am in need of some very simple javascript to validate email address and a phone number from a form.
The email address only needs to:
1. Check that the box is not empty.
2. Check that the text imputted contains an '@' symbol.
3. Check that the text imputted contains atleast 1 Period.
The phone number only needs to:
1. Check that the box is not empty.
2. Check that there is no more than 11 characters.
3. check that only numeric characters have been inputted.
I would like it to report (failure) back as text on the page under the box that has the problem rather than a window.