Solved! Go to Solution.
// add the counties layer countiesLayer = new esri.layers.ArcGISDynamicMapServiceLayer("http://asdf/ArcGIS/rest/services/Counties/MapServer", { id: "countiesLayer" }); map.addLayer(countiesLayer);
Apologies if I should not reply to this older thread, but I am also experiencing this in firefox 19.0.2 with the 3.3 api and thought it was worth mentioning since I ended up here and others may get here when having the same problem.
In my code it seems to be related to calling map.addLayer with a ArcGISDynamicMapServiceLayer. If I comment out the addLayer calls for all the ArcGISDynamicMapServiceLayers the page will complete loading with ctrl+f5 and on the initial load. I'm also adding some graphics layers and their map.addLayer does not cause the problem. Only the ArcGISDynamicMapServiceLayer layers are causing this to show up for me. The actual content of the ArcGISDynamicMapServiceLayer loads and the map is fully functional. Firefox just seems to think the page is still loading.
Example of my code adding the dynamic layer:// add the counties layer countiesLayer = new esri.layers.ArcGISDynamicMapServiceLayer("http://asdf/ArcGIS/rest/services/Counties/MapServer", { id: "countiesLayer" }); map.addLayer(countiesLayer);