var last_layer = 1;
    function showLayer(layernum)
    {
        if (layernum == 1) //multimedia
        {
	        document.img_multimedia.src='/images/multimedia_tab.gif';
		    document.img_benefits.src='/images/benefits_tab_gray.gif';
            document.img_specification.src='/images/specification_tab_gray.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab_gray.gif';
		    document.img_reviews.src='/images/reviews_tab_gray.gif';
		    document.img_guarantee.src='/images/guarantee_tab_gray.gif';
		    document.img_related_items.src='/images/related_items_tab_gray.gif';
		    document.getElementById('multimedia').style.display = 'block';
		    document.getElementById('benefits').style.display = 'none';
		    document.getElementById('specifications').style.display = 'none';
		    //document.getElementById('manufacturer').style.display = 'none';
		    document.getElementById('reviews').style.display = 'none';
		    document.getElementById('guarantee').style.display = 'none';
		    document.getElementById('related').style.display = 'none';
        }
        if (layernum == 2) //specs
        {
	        document.img_multimedia.src='/images/multimedia_tab_gray.gif';
		    document.img_benefits.src='/images/benefits_tab_gray.gif';
            document.img_specification.src='/images/specification_tab.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab_gray.gif';
		    document.img_reviews.src='/images/reviews_tab_gray.gif';
		    document.img_guarantee.src='/images/guarantee_tab_gray.gif';
		    document.img_related_items.src='/images/related_items_tab_gray.gif';
		    document.getElementById('multimedia').style.display = 'none';
		    document.getElementById('benefits').style.display = 'none';
		    document.getElementById('specifications').style.display = 'block';
		    //document.getElementById('manufacturer').style.display = 'none';
		    document.getElementById('reviews').style.display = 'none';
		    document.getElementById('guarantee').style.display = 'none';
		    document.getElementById('related').style.display = 'none';
        }
        if (layernum == 3) //benefits
        {
	        document.img_multimedia.src='/images/multimedia_tab_gray.gif';
		    document.img_benefits.src='/images/benefits_tab.gif';
            document.img_specification.src='/images/specification_tab_gray.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab_gray.gif';
		    document.img_reviews.src='/images/reviews_tab_gray.gif';
		    document.img_guarantee.src='/images/guarantee_tab_gray.gif';
		    document.img_related_items.src='/images/related_items_tab_gray.gif';
		    document.getElementById('multimedia').style.display = 'none';
		    document.getElementById('benefits').style.display = 'block';
		    document.getElementById('specifications').style.display = 'none';
		    //document.getElementById('manufacturer').style.display = 'none';
		    document.getElementById('reviews').style.display = 'none';
		    document.getElementById('guarantee').style.display = 'none';
		    document.getElementById('related').style.display = 'none';
        }
        if (layernum == 4) //manufacturer
        {
	        document.img_multimedia.src='/images/multimedia_tab_gray.gif';
		    document.img_benefits.src='/images/benefits_tab_gray.gif';
            document.img_specification.src='/images/specification_tab_gray.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab.gif';
		    document.img_reviews.src='/images/reviews_tab_gray.gif';
		    document.img_guarantee.src='/images/guarantee_tab_gray.gif';
		    document.img_related_items.src='/images/related_items_tab_gray.gif';
		    document.getElementById('multimedia').style.display = 'none';
		    document.getElementById('benefits').style.display = 'none';
		    document.getElementById('specifications').style.display = 'none';
		    //document.getElementById('manufacturer').style.display = 'block';
		    document.getElementById('reviews').style.display = 'none';
		    document.getElementById('guarantee').style.display = 'none';
		    document.getElementById('related').style.display = 'none';
        }
        if (layernum == 5) //reviews
        {
	        document.img_multimedia.src='/images/multimedia_tab_gray.gif';
		    document.img_benefits.src='/images/benefits_tab_gray.gif';
            document.img_specification.src='/images/specification_tab_gray.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab_gray.gif';
		    document.img_reviews.src='/images/reviews_tab.gif';
		    document.img_guarantee.src='/images/guarantee_tab_gray.gif';
		    document.img_related_items.src='/images/related_items_tab_gray.gif';
		    document.getElementById('multimedia').style.display = 'none';
		    document.getElementById('benefits').style.display = 'none';
		    document.getElementById('specifications').style.display = 'none';
		    //document.getElementById('manufacturer').style.display = 'none';
		    document.getElementById('reviews').style.display = 'block';
		    document.getElementById('guarantee').style.display = 'none';
		    document.getElementById('related').style.display = 'none';
        }
        if (layernum == 6) //guarantee
        {
	        document.img_multimedia.src='/images/multimedia_tab_gray.gif';
		    document.img_benefits.src='/images/benefits_tab_gray.gif';
            document.img_specification.src='/images/specification_tab_gray.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab_gray.gif';
		    document.img_reviews.src='/images/reviews_tab_gray.gif';
		    document.img_guarantee.src='/images/guarantee_tab.gif';
		    document.img_related_items.src='/images/related_items_tab_gray.gif';
		    document.getElementById('multimedia').style.display = 'none';
		    document.getElementById('benefits').style.display = 'none';
		    document.getElementById('specifications').style.display = 'none';
		    //document.getElementById('manufacturer').style.display = 'none';
		    document.getElementById('reviews').style.display = 'none';
		    document.getElementById('guarantee').style.display = 'block';
		    document.getElementById('related').style.display = 'none';
        }  
        if (layernum == 7) //related
        {
	        document.img_multimedia.src='/images/multimedia_tab_gray.gif';
		    document.img_benefits.src='/images/benefits_tab_gray.gif';
            document.img_specification.src='/images/specification_tab_gray.gif';
		    //document.img_manufacturer.src='/images/manufacturer_tab_gray.gif';
		    document.img_reviews.src='/images/reviews_tab_gray.gif';
		    document.img_guarantee.src='/images/guarantee_tab_gray.gif';
		    document.img_related_items.src='/images/related_items_tab.gif';
		    document.getElementById('multimedia').style.display = 'none';
		    document.getElementById('benefits').style.display = 'none';
		    document.getElementById('specifications').style.display = 'none';
		    //document.getElementById('manufacturer').style.display = 'none';
		    document.getElementById('reviews').style.display = 'none';
		    document.getElementById('guarantee').style.display = 'none';
		    document.getElementById('related').style.display = 'block';
        }               
        last_layer=layernum;
    }