I have been working on Ajax. The application, all in javascript at the client, works great on firefox, safari, and chrome, but not on FirefoxDeveloperEdition. The issue is at exactly the request.open statement. It does not work on FirefoxDeveloperEdition. In the console I get the error ":" --- that is all, just the colon. As I said, that statement works perfectly on Firefox. I have the most recent version of all apps. The selection of XMLHttpRequest is working the same in both Firefox and FirefoxDeveloperEdition. Either FirefoxDeveloperEdition is not backward compatible or not meant to be, and I cannot tell which. Help desired.