PageFocus is a JavaScript that allows to determine if and how frequently users abandon web pages by switching to another window or browser tab.
The PageFocus.html file is part of the supplemental material of the article PageFocus: Using Paradata to Detect and Prevent Cheating on Online Achievement Tests by Birk Diedenhofen and Jochen Musch. The JavaScript section of the file includes version 1.3 of the PageFocus script.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program.