function roll(number)  
   {                                                                                                                                                                                                                                                                          
   if (document.getElementById("table"+number).style.display == "block")
      {
      document.getElementById("table"+number).style.display = "none";  
      document.getElementById("up"+number).style.display = "none";  
      document.getElementById("down"+number).style.display = "block";                                           
      }
      else
      {
      document.getElementById("table"+number).style.display = "block";  
      document.getElementById("up"+number).style.display = "block";  
      document.getElementById("down"+number).style.display = "none";                                              
      }
  }