pg = 1;
ProxAnt = function(act){
   if(act == "ant" && pg > 1){
      pg--;
       if(pg < 10){
         pg = "0"+pg;
      }
      location.href = pg+".htm";
   }
   else
   {
    if(act == "prox" && pg < 4 /*coloca o numero de paginas no lugar do 4*/){
        pg++;
         if(pg < 10){
            pg = "0"+pg;
         }
        location.href = pg+".htm";
    }
   }
}