I learned something today.
I use NetBeans 6.8 PHP for developing web apps. My external web browser is Firefox 3.6.
In the the HTML editor of NetBeans you right-click and select View. This sends the HTML file to Firefox. No requests will ever be generated.
So to correct this use HTTP://localhost instead of file://c:\whatever.
In the editor “run” the file instead of “view” (CTL-F6). BTW, why would anyone ever want to view the HTML instead of run it?
This really helped me out when debugging jQuery post request, using JSON format.