exemple :



code :

var ua = navigator.userAgent.toLowerCase();
var is_amiga = (ua.indexOf("amiga") != -1);
var preloadFlag = false;
window.onload = preloadImages;
    
function changeImages(iName, iSource)
{
   if (document.images)
   {
      if (is_amiga)
      {
         document.images[iName].src = iSource;
      }
      else if (preloadFlag == true)
      {
         for (var i = 0; i < changeImages.arguments.length; i += 2)
         {
            document[changeImages.arguments[i]].src = changeImages.arguments[i + 1];
         }
      }
   }
}

function preloadImages()
{
   if (document.images)
   {
      bnews_over = newImage("02.gif");
      preloadFlag = true;
   }
}
    
function newImage(arg)
{
   if (document.images)
   {
      rslt = new Image();
      rslt.src = arg;
      return rslt;
   }
}

< A href="perm_img.html"
onmouseout="changeImages('bnews', '01.gif'); return true;"
onmouseover="changeImages('bnews', '02.gif'); return true;">
< IMG alt=News border=0 height=20 name=bnews src="01.gif" width=41>