//
// Global variable listing images on each page,
// which should all be the same because they're written by topicmenu.js and header.js!
//
var documentImages = new Array(),
    ro_placeholder = new Image();

ro_placeholder.src = "images/placeholder.gif";
		
// All images
if (document.images) 
{
	documentImages['support_material'] = new NOKIAImageCollection( 'support_material', 'h_support_material', false );
	documentImages['exit'] = new NOKIAImageCollection( 'exit', 'h_exit', false );
	documentImages['intro'] = new NOKIAImageCollection( 'intro', 'intro', true );
	documentImages['overview'] = new NOKIAImageCollection( 'overview', 'overview', true );
	documentImages['features'] = new NOKIAImageCollection( 'features', 'features', true );
	documentImages['sellit'] = new NOKIAImageCollection( 'sellit', 'sellit', true );
	documentImages['specs'] = new NOKIAImageCollection( 'specs', 'specs', true );
	documentImages['enhancements'] = new NOKIAImageCollection( 'enhancements', 'enhancements', true );
	documentImages['faq'] = new NOKIAImageCollection( 'faq', 'faq', true );
	documentImages['quiz'] = new NOKIAImageCollection( 'quiz', 'quiz', true );
}


// Function for Normal Image
function N_img(imgName)
{
	if (document.images) 
	{
        if (documentImages[imgName])
        {
    		documentImages[imgName].showNormal();
        }
		
		if (document.images.rollover)
		{
			document.images.rollover.src = ro_placeholder.src;
		}	
	}
}
	
// Function for Mouseover Image
function MO_img(imgName)
{
	if (document.images) 
	{
		if ( documentImages[imgName] )
		{
			documentImages[imgName].showMouseOver();
			documentImages[imgName].showRollOver();
		}
	}
}

	// Class ImageCollection
	function NOKIAImageCollection( imageName, sourceName, hasRollOver )
	{
        // private properties
		this.imageName = imageName;
	
		this.normal = new Image();
		this.normal.src = 'images/n_' + sourceName + ".gif";
				
		this.mouseOver = new Image();
		this.mouseOver.src = 'images/mo_' + sourceName + ".gif";

		if ( hasRollOver )
		{
			this.rollOver = new Image();
			this.rollOver.src = 'images/ro_' + sourceName + ".gif";
		}
		
		// accessor methods
		this.getNormalSource = __nokiaimagecollection_getNormalSource;		
		this.getMouseOverSource = __nokiaimagecollection_getMouseOverSource;		
		this.getRollOverSource = __nokiaimagecollection_getRollOverSource;		
		
		this.showNormal    = __nokiaimagecollection_showNormal;
		this.showMouseOver = __nokiaimagecollection_showMouseOver;
		this.showRollOver  = __nokiaimagecollection_showRollOver;
	}
	
	function __nokiaimagecollection_getNormalSource()
	{
		return this.normal.src;
	}
		
	function __nokiaimagecollection_getMouseOverSource()
	{
		return this.mouseOver.src;
	}
		
	function __nokiaimagecollection_getRollOverSource()
	{
		if ( this.rollOver )
		{
			return this.rollOver.src;
	    }
		
		return false;
	}
	
	function __nokiaimagecollection_showNormal()
	{
		document.images[this.imageName].src = this.getNormalSource();
	}
	
	function __nokiaimagecollection_showMouseOver()
	{
		document.images[this.imageName].src = this.getMouseOverSource();
	}
	
	function __nokiaimagecollection_showRollOver()
	{
		if ( this.rollOver )
		{
			if ( document.images.rollover )
			{
				document.images.rollover.src = this.getRollOverSource();
			}
		}
		else
		{
			if ( document.images.rollover )
			{
				document.images.rollover.src = ro_placeholder.src;
			}	
		}
	}