I was thinking of editing my comment to add "Or be able to support filetypes other than HTML", but I suppose in our glorious "everything is the browser" future, filetypes other than HTML are as anachronistic as 8" floppy disks.
FWIW, you can use data URLs to include any type of file in your HTML, and with <a download='filename' href='data:…'> browsers will allow you to save the file.
