Problems in Browsers

Just recently I realised that my routines for using Google Map to display GPX files do not work at all in Google Chrome and Firefox. I had developed the code by testing in MS Explorer 7, hoping that my attempts on being cross-browser compatible would pay off. But no, as I noticed a few days ago, the map is not being updated and does not show the actual track; instead it remains at the default location. I have to explore what the technical issue is. Might be that an error is thrown after which the browser stops executing JavaScript code and does not progress to the point where the map is to be shifted to the new location. Due to the limited debugging capabilities of the browser / editor environment which I am using (Homesite), this will take a while to fix...