function popUpCentered(URL,popUpWidth,popUpHeight)
	{
	var popUp = self.open(URL, '', 'width=' + popUpWidth + ', height=' + popUpHeight);

	//position popup window
	var x = (screen.width - popUpWidth) / 2;	
	var y = (screen.height - popUpHeight) / 2;	
	//not exact center
	y = y - (y/10); 
	popUp.moveTo(x, y);
	return false;
	}