var displayedIFrames = new Array();
	
	function displaySubMenu ( element, iframePrefix, ulPrefix, ID )
	{
		setSubMenuClasses ( element, true, iframePrefix, ulPrefix, ID );
	}

	function hideSubMenu ( element, iframePrefix, ulPrefix, ID )
	{
		setSubMenuClasses ( element, false, iframePrefix, ulPrefix, ID );
	}
	
	function setSubMenuClasses ( element, shouldDisplay, iframePrefix, ulPrefix, ID )
	{
		var ulElement = document.getElementById(ulPrefix + ID);
		
		if ( ! ulElement )
			return false;
		
		if ( ulElement.className == ( shouldDisplay ? 'visible' : '' ) )
			return true;
			
		ulElement.className = ( shouldDisplay ? 'visible' : '' );
		
		if ( _vp_useIFrame )
		{
			if ( shouldDisplay && ( iframe = document.getElementById ( iframePrefix + ID ) ) )
			{
				iframe.style.display	= 'block';
				iframe.style.height		= ulElement.offsetHeight;
			}
			else if ( ! shouldDisplay )
				iframe.style.display	= 'none';
		}
			
		return true;
	}