what about something like:
$(document).ready(function()
{
$(".navigation a").hover(function()
{
var href=$(this).attr("href");
$("#content").fadeOut("fast", function()
{
$("#content").empty();
$("#content").load(href+" #content", function()
{
$("#content").fadeIn("fast");
});
});
},
function(){});
});
Of course, with this you will need to have jquery.
this will cause the content area to disappear, load new content, and then disappear.