You may not be aware of the dangers of JavaScript — a problem we've deemed The JavaScript Trap — proprietary software running on your computer, inside your web browser.
Danger! Your very soul is at risk!
This page is even worse: http://www.gnu.org/philosophy/javascript-trap.html
Silently loading and running nonfree programs is one among several issues raised by "web applications". The term "web application" was designed to disregard the fundamental distinction between software delivered to users and software running on the server.
Beware, dear reader. They may be starting with this fundamental distinction... but your children will be next!