How does HTML5 input type email works without top level domain name

Question

The input type = email tag in html5 works even if the top level domain name is not present

Answer 1

Because bar is a valid hostname, which makes foo@bar a valid email address.

Chrome is not going to check for you whether the address or host are actually in use, only whether the semantics are correct.

See http://en.wikipedia.org/wiki/Email_address#Domain_part for examples of valid email addresses.