It contain's 4,000 <em> with jQuery's mouseover and mouseout events.
With Firefox 3.0.6 (jQuery 1.3.1) it can not be reloaded. (Because jQuery want unbind the events?)
It can be reloaded with Internet Explorer 7 or Opera too. With FF 2 it waits a bit less.
Try the another example, wich uses HTML's onmouseover and onmouseout events!