function toggleOn (obj) {
      obj.src = obj.src.replace("_off", "_on");
   }

   function toggleOff (obj) {
      obj.src = obj.src.replace("_on", "_off");
   }   
   
   //preloaded images for the english sidemenu
      image1 = new Image();
      image1.src = "images/btn_home_e_on.gif";
   
      image2 = new Image();
      image2.src = "images/btn_about_us_e_on.gif";
   
      image3 = new Image();
      image3.src = "images/btn_our_services_e_on.gif";
   
      image4 = new Image();
      image4.src = "images/btn_whats_e_on.gif";   
   
      image5 = new Image();
      image5.src = "images/btn_info_tools_e_on.gif";
	 
      image6 = new Image();
      image6.src = "images/btn_publications_e_on.gif";
	
	  image7 = new Image();
      image7.src = "images/btn_our_associates_e_on.gif";
	
	  image8 = new Image();
      image8.src = "images/btn_links_e_on.gif";
	
	  image9 = new Image();
      image9.src = "images/btn_contacts_e_on.gif";