Can I make my application open up a new email in yahoo mail or gmail web clients?

I'm building an address book application. I'd like to allow users to click on a contact in my application, and be directed to their yahoo or gmail webmail开发者_开发知识库, to the compose page, with the "to" field populated with data that I supply. Is this possible?

As for Yahoo I really don't know. For Gmail you can. Just use the bellow URL (changing variables accordingly).

https://mail.google.com/mail/?view=cm&fs=1&tf=1&to=user@example.com

It was just yesterday that I asked a if anyone knew where to find all of Gmail's variables.