LoadMovie, if not already loaded

programming flash
1

I’m trying to make a navigation, where it will only load the page if it is not already on the screen. Here is the code I have for a button, but I can’t find the property I need to address the loaded movie’s name.

on (release) {
	if (_root.content.PROPERTY != "body.swf") {
		_root.content.loadMovie("body.swf");
	}
}

Any help is appreciated,
PXC