Credits: I "stole this code" (Abbie Hoffman style) from an old fixthecfaa.com campaign, then cut away half of it.
Note that I take close.png from thedod.github.io and it's probably more sanitary to serve it locally ;)
See this "on a real site" at thedod.github.io.
If you click the close button and want to see the dialog again, clear the _dp_b4tn cookie.
Please let me know if you make it better.
Peace,
The Dod