This page demonstrates a bug in mozilla as of 1.3a. The form above contains a div into which an unordered list is inserted via javascript at load time. When the button is clicked it will jump down (along with anything else on the page) about an eigth of an inch and not do anything. When it is clicked a second time it does the submission.
The click needs to be at the top of the button in the part that is not overlapped with the moved button or it will work correctly.
If the button is tabbed to the space bar will cause it to go on to the next page. Resizing the screen causes it to redraw correctly.
As to why insert an empty <ul>, this script is part of one that builds a list dynamically as part of a webapp and the empty <ul> keeps the page from validating. (Validation being one of the unit tests.)