function rand ( n )
 {
  return ( Math.floor ( Math.random ( ) * n + 1 ) );
 }

var link  = new Array();
var opac  = new Array();
var shln  = new Array();
var shown = new Array();

i       = 1;
link[i] = "<a href=\"http://aquarium.etop20.com\" target=\"_blank\"><img src=\"http://aquarium.etop20.com/button-u-janhvizdak.gif\" alt=\"Tropical Fish Top Sites\" border=\"0\" /></a>";
opac[i] = 70;
i++;

//link[i] = "<a href=\"http://www.greatpetwebsites.com/\" target=\"_blank\"><img src=\"http://www.greatpetwebsites.com/button.php?u=janhvizdak\" alt=\"Great Pet Websites\" border=\"0\" /></a>";
//opac[i] = 1770;
//i++;

link[i] = "<a href=\"http://www.animal-topsites.de/\"><img src=\"http://www.animal-topsites.de/button.php?u=janhvizdak\" alt=\"Animal Topsites\" border=\"0\" width=\"88\" height=\"31\" /></a>";
opac[i] = 755;
i++;

link[i] = "<a href=\"http://www.aquariarank.com/\" target=\"_blank\"><img src=\"http://www.aquariarank.com/button.php?u=janhvizdak\" alt=\"AquariaRank - Top Aquarium Sites\" border=\"0\" /></a>";
opac[i] = 55;
i++;

link[i] = "<a href=\"http://www.exoticpetsites.com\" target=\"_blank\"><img src=\"http://www.exoticpetsites.com/button.php?u=janhvizdak\" alt=\"Exotic Pet Sites\" border=\"0\" width=\"88\" height=\"31\" /></a>";
opac[i] = 8618;
i++;

link[i] = "<a href=\"http://www.rankyourtank.co.uk/index.php?a=rate&amp;u=janhvizdak\" target=\"_blank\"><img src=\"http://www.rankyourtank.co.uk/button.php?u=janhvizdak\" alt=\"Rank Your Tank\" border=\"0\" /></a>";
opac[i] = 55;
i++;

link[i] = "<a href=\"http://www.fishtopsites.com/\" target=\"_blank\"><img src=\"http://www.fishtopsites.com/button.php?u=janhvizdak\" alt=\"Fish Topsites\" border=\"0\" /></a>";
opac[i] = 3001;
i++;

link[i] = "<a href=\"http://www.top100add.com/\" target=\"_blank\"><img src=\"http://www.top100add.com/button.php?u=janhvizdak\" alt=\"TOP100ADD.COM - ADD YOUR SITE, BOOST YOUR TRAFFIC.\" border=\"0\" /></a>";
opac[i] = 200;
i++;

link[i] = "<a href=\"http://bestanimalsites.com/\" target=\"_blank\"><img src=\"http://bestanimalsites.com/button.php?u=janhvizdak\" alt=\"Best Animal Sites - Animal &amp; Pet Topsites\" border=\"0\" width=\"88\" height=\"31\" /></a>";
opac[i] = 647;
i++;

link[i] = "<a href=\"http://www.aquariumlife.net\" target=\"_blank\"><img src=\"http://rank.aquariumlife.net/button.php?u=janhvizdak\" alt=\"Aquarium Life Popular Sites for Fish Information, DIY Aquarium Projects, Aquarium Forums and More!\" border=\"0\" /></a>";
opac[i] = 577;
i++;

link[i] = "<a href=\"http://bestpetsites.co.uk/\" target=\"_blank\"><img src=\"http://bestpetsites.co.uk/button.php?u=janhvizdak\" alt=\"Best Pet Sites\" border=\"0\" /></a>";
opac[i] = 30;
i++;

//link[i] = "<a href=\"http://www.faunatopsites.com/\" target=\"_blank\"><img src=\"http://www.faunatopsites.com/button.php?u=janhvizdak\" alt=\"Fauna Top Sites\" border=\"0\" /></a>";
//opac[i] = 6096;
//i++;

i--;
sum     = 0;
shln[0] = 0;
for(j=1;j<=i;j++)
 {
  sum      = sum + opac[j];
  shln[j]  = sum;
  shown[j] = 0;
 }

document.write("<p>");

found = 0;
while(found<4)
 {
  r = rand(sum);
  for(k=1;k<=i;k++)
   {
    if( (r>=shln[(k-1)]) && (r<shln[k]) && (shown[k]==0) )
     {
      found++;
      shown[k] = 1;
      if(found<4)
       document.write(link[k] + " ");
        else
         document.write(link[k]);
     }
   }

 }
document.write("</p>");