This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Provide a "download button", and let the user save the generated file to the local disk ? Most users would just not use a browser which let any page on the web mess around with their hard discs. Imagine what might happen if the site "created" c:\windows\system.dat or /etc/password.