if (document.images) {

//rollovers
		research = new Image();
		research_down = new Image();
		methodology = new Image();
		methodology_down = new Image();
		events = new Image();
		events_down = new Image();
		resources = new Image();
		resources_down = new Image();
		services = new Image();
		services_down = new Image();
		about = new Image();
		about_down = new Image();

		research.src = "../_images/btn-research-0.gif";
		research_down.src = "../_images/btn-research-1.gif";
		methodology.src = "../_images/btn-methodology-0.gif";
		methodology_down.src = "../_images/btn-methodology-1.gif";
		events.src = "../_images/btn-events-0.gif";
		events_down.src = "../_images/btn-events-1.gif";
		resources.src = "../_images/btn-resources-0.gif";
		resources_down.src = "../_images/btn-resources-1.gif";
		services.src = "../_images/btn-services-0.gif";
		services_down.src = "../_images/btn-services-1.gif";
		about.src = "../_images/btn-about-0.gif";
		about_down.src = "../_images/btn-about-1.gif";

//descriptors
		blank_desc = new Image();
		research_desc = new Image();
		methodology_desc = new Image();
		events_desc = new Image();
		resources_desc = new Image();
		services_desc = new Image();
		about_desc = new Image();

		blank_desc.src = "../_images/img-nav-desc-blank.gif";
		research_desc.src = "../_images/img-nav-desc-research.gif";
		events_desc.src = "../_images/img-nav-desc-events.gif";
		methodology_desc.src = "../_images/img-nav-desc-methodology.gif";
		resources_desc.src = "../_images/img-nav-desc-resources.gif";
		services_desc.src = "../_images/img-nav-desc-services.gif";
		about_desc.src = "../_images/img-nav-desc-about.gif";

}

function buttonOn(imageName) {
	if (document.images) {
		document[imageName].src = eval(imageName+"_down.src")
		document['desc'].src = eval(imageName+"_desc.src")
		}
	}

function buttonOff(imageName) {
	if (document.images) {
		document[imageName].src = eval(imageName+".src")
		document['desc'].src = eval("blank_desc.src")
		}
	}