Does anybody know how to load an IFrame in the background of the browser, without interfering with running JQuery animations?

I have this page that contains an IFrame. Using JQuery I set the src attribute to a certain url.

But my page is also showing an animating span continuously. (kind of progress-bar). When the IFrame is loading a large image of the external url, the browser stops temporarily, until the images is loaded, so my animation is stopped for an instant, and then continues.