JQuery :: Calling Browser Plugin Object On True Condition?

I am using this Browser Plugin call: world = new MTSPlugin( '../obj/main.mtx', '100%', '100%', '', 'simple', ''); in the middle of my page, where I want to load this object. (It is a 3d rendering modul Viewpoint Player)

Now I want to add a browser check, as this plugin runs only in IE. When I dedect that the page is loaded with IE, I am writing via Jquery a class name into my body tag.

I thought, it would work if I do the following:

if($('body').attr('class').length > 1){
world = new MTSPlugin( '../obj/main.mtx', '100%', '100%', '', 'simple', '');
}

But for some reason, the if fails, as it seem that the plugin is called earlier than the jquery browser check, so the class name is not set at this point.

Then I thought, making a function arround and call it onLoad within the body tag.
Which has the disatvantage that the MTS Plugin is loading at the worng place on the page.

What I want, is that the call to the object "world = new MTSPlugin( '../obj/main.mtx', '100%', '100%', '', 'simple', '');"
is only at a trie condition at the place where it should be...