Comment 57 for bug 728798

In case it helps you repro... This page will fail after the 3rd refresh:
http://www.screencast-o-matic.com/detect-full-url.html

After the 3rd refresh the getDocumentBase() function on the applet returns null and you can no longer call functions on the applet via javascript.

Here's a screencast showing the failure:
http://www.screencast-o-matic.com/watch/cXee0w2Xb

Also here's another page which uses a relative path to the jar which also fails on the 3rd load but the error in the console is different:
http://www.screencast-o-matic.com/detect.html