From Javascript, I don't think so, from HTML, I'm pretty certain not.
If you have access to .NET, it's pretty simple. You can either send the same email twice, or send it to one of the recipients as a CC or BCC.
There is a generic C# routine for sending emails here:
Sending an Email in C# with or without attachments: generic routine.[
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A System.Net.MailMessage has both CC and BCC fields, if you need to go that route - set them just like the To address.