function lightup(imageobject, opacity){
         if (navigator.appName.indexOf("Netscape")!=-1
          &&parseInt(navigator.appVersion)>=5)
            imageobject.style.MozOpacity=opacity/100
         else if (navigator.appName.indexOf("Microsoft")!= -1 
          &&parseInt(navigator.appVersion)>=4)
            imageobject.filters.alpha.opacity=opacity
        }