Sending email from a webpage

>I have a web application which people connect to and I generate an
output file for users when they click on a link. Currently, they are
saving this file and then emailing it inside their organization to
other staff members.
>
I would like to automate the process so they can click the link and
have an email automatically sent off. However, I cannot do this
serverside for security reasons, all emails have to be sent *by the
user* using their internal mail server.
>
Any suggestions?
>
Thanks