PHP Send E-mail -> Multiple Recipients -> jQuery Validation

Hi Guys,

I am using this jQuery PHP send-mail form:
http://www.raymondselda.com/php-contact-form-with-jquery-validation/

I'd like to ask you if you could suggest me ready solution how to edit above code to accept and validate multiple e-mail separated by comma.

Example:

When I type first e-mail:
hello@email.com

it will automatically add comma and space so I can type another e-mail in this one field:
hello@email.com, hello2@email.com, hello3@email.com, etc.

There will be maximum of 20 recipients.

I am sure I'm not the only one who would be delighted by this solution as I couldn't find any ready made jQuery multiple e-mail validation form.

Thank you in advance!