Just experienced strangeness with JavaScript in browser which has various maintenance and security implications.
While testing a web site using Jetty 6.1.12 and Eclipse with Jetty plugin, I noticed that somehow magically after requesting a web page, my files were ending up with extra characters at the end and I wasn't editing them. This happened both with HTML files and JavaScript files. It looked like the file would get the last 150 or so characters at the end of the document copied and pasted to the end of it. I would fix the file. Open it up to verify my fixes were saved. Then I would start and run the application and the problem would happen all over again.
This is odd - The source files shouldn't get edited and saved to disk when I make request to the web site. What would be changing them - the browser? Jetty? Jetty Eclipse Plugin? The OS? Browser plugin? Virus scanning software? Something in network? This is where it gets tricky.
The source files shouldn't get edited and saved to disk when I make request to the local web site. That should never alter the source code in the original web site. The original source files were altered, not just the code shown by view source in the browser or cached JavaScript source.
I figured out a few of things:
1. Could fix the files (delete the extra characters) in WordPad, but NotePad wouldn't make the changes stick for some reasons. I also realized later that NotePad wasn't alerting me when it didn't save the file if locked. WordPad would tell me. I had to shut down the web server to change the files even after setting ofline storage to 0 in FireFox.
2. After fixing the files they would continue to get corrupted. I finally made them read only to try to resolve the problem and changed my logging to indicate any time the files changed or there was an access error to try to pinpoint what was changing them. Even when the files were read only they still got changed and no logs indicating how they were changed or what changed them.
3. JavaScript functions in HTML file and did not have issues and the page loaded consistently on a few tests (did not test extensively).
4. FireFox does not log an error if your JavaScript src file path is incorrect. It just tells you a particular function is missing.
5. I realized even though I thought I turned off Firefox caching was still caching JavaScript files. Closing and opening browser would ensure I was getting the right file.
6. At one point I noticed that I had two opening head tags instead of correctly closing the head tag. That may have caused errors - but shouldn't have caused my source files to get altered.
7. I started working offline to remove any issues related to things getting cached somewhere related to being on the network even though the web page I am requesting is localhost.
8. When I initially had this problem I checked in both IE and FireFox and the same thing seemed to be happening, but perhaps one of them was altering the file so when I checked in the other I got the same result.
I don't know which of the above actually solved the problem but I'm not seeing it anymore and don't have time to explore this further. Just posting it online in case the makers of all this software want to figure out what in the world caused this because having software rewrite your source files when a web page is requested - is a bit troubling.
