Some elements are set to display: none, like the .flash and .hidden CSS classs. The reason for this is to prevent exactly what you are describing. You don't want those elements to be displayed before JavaScript has a chance to load. Once the page is fully loaded, then JavaScript makes these elements visible.
- [web2py] Strange Flashing of Elements David J.
- [web2py] Re: Strange Flashing of Elements Ross Peoples

