You can create a URL to open the mail client, but you'd be relying on the user to press send.
You should be able to use window.location=mailto;... to automatically open the mail client
<a href="mailto:email@example.com?subject=sample mailto link&body=email text here">Mailto Link</a>
To send an email without user intervention you'll need something like the EmailComposer PhoneGap plugin https://github.com/purplecabbage/pho.../EmailComposer
There were some people talking about similar functionality on the PhoneGap google group. Search for "in app email"