if (document.images) {
	company = new Image();
  	company.src = "/img/design/btn_company.jpg";
  	company_on = new Image();
  	company_on.src = "/img/design/btn_company_on.jpg";

  	services = new Image();
  	services.src = "/img/design/btn_services.jpg";
  	services_on = new Image();
  	services_on.src = "/img/design/btn_services_on.jpg";
    
  	research = new Image();
  	research.src = "/img/design/btn_research.jpg";
  	research_on = new Image();
  	research_on.src = "/img/design/btn_research_on.jpg";
  
  	locations = new Image();
  	locations.src = "/img/design/btn_locations.jpg";
  	locations_on = new Image();
  	locations_on.src = "/img/design/btn_locations_on.jpg";
    
  	contact = new Image();
  	contact.src = "/img/design/btn_contact.jpg";
  	contact_on = new Image();
  	contact_on.src = "/img/design/btn_contact_on.jpg";
}

function switchOn(imgName) {
    if (document.images) {
      document[imgName].src = eval(imgName + "_on.src");
    }
}
  
function switchOff(imgName) {
    if (document.images) {
      document[imgName].src = eval(imgName + ".src");
    }
}