hiding a flash swf to the left

I have a swf object that is to the left of a header div that is 1000px wide. the swf is 303px wide. How would I make the swf on the left hide behind the window when the windows is only, say, 1050px wide?

Kinda like how this one is: http://eu.blizzard.com/diablo3/index.xml

notice how the object get hidden, still plays, but doesn't lose it's aspect ratio? How does someone do this?

the code is set up like this:

<div class="swf">
  object
</div>
<div class="header">
  nav stuff
</div>

I've tried to make the header 1303 wide, but then on resize it just stops and keeps moving everything that is u开发者_Python百科nder it, and the swf stays put

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Why dont you make the css property position on class swf to absolute and and z-index to -1 it will hide behind the header and then you can let the header be 1000px