I need to open an email popup in edit mode. The email needs to have either a HTML table in the body or an excel sheet with the data attached to it.

The email generation in edit mode is currently being achieved using "mailTo" from JavaScript. But it seems mailTo doesn't support HTML content or attaching files.

The goal is to minimise the number of steps needed to view the data.

Things that don't work:

1. I can't use an EML file because it's opening in a way that doesn't allow me to edit the email and I've to move it to drafts in order to edit it - which fails the whole purpose. If there's a way to open it in the edit mode, please do suggest.
2. AppleScript also seems to have stopped supporting HTML content.
3. Cannot generate a new link to download the excel file because that's too many steps to view the data.
4. javax.mail package - this seems to work only to directly send the email which doesn't serve my purpose. I also used this for my EML approach (1)

Technologies available: Java 8, AngularJS, JavaScript

Any help or suggestions are appreciated. Thanks in advance for your time.