if (document.images)
   {
     socialon= new Image();
     socialon.src="../common/images/nav/social_ro.gif";  
     socialoff= new Image();
     socialoff.src="../common/images/nav/social.gif";
     
     healthon= new Image();
     healthon.src="../common/images/nav/health_ro.gif";  
     healthoff= new Image();
     healthoff.src="../common/images/nav/health.gif";     
     
     economicon= new Image();
     economicon.src="../common/images/nav/economic_ro.gif";  
     economicoff= new Image();
     economicoff.src="../common/images/nav/economic.gif";   

   }
   
   function img_act(imgName) {
		imgOn = eval(imgName + "on.src");
		document [imgName].src = imgOn;
   } 


function img_inact(imgName) {
		imgOff = eval(imgName + "off.src");
		document [imgName].src = imgOff;  
  }