function gofilter(filter)
  {
    var filter = document.modelform.model.value;

    var dest = "";
    switch(filter)
    {
      case "MA0950":
      case "MA1200":
        dest = "MAF-1.html";
        break;
      case "HD07W":
      case "HD08W":
      case "HD08WV":
      case "HD6000":
      case "HD8000":
      case "HD8001":
      case "HD10W":
      case "HD12W":
      case "HD12WV":
      case "HD13W":
      case "HD14W":
      case "HD15W":
        dest = "HDC-1.html";
        break;
      case "HD1200":
      case "HD1202":
      case "HD1204":
      case "HD1300":
      case "HD1303":
      case "HD1300W":
      case "HD1305":
      case "HD1405":
      case "HD1406":
      case "HD1407":
        dest = "HDC-12.html";
        break;
      case "HD230":
        dest = "HDC23.html";
        break;
      case "HD1211":
      case "HD2412":
      case "HD1205":
      case "HD7002":
      case "HD7005":
      case "HD500":
        dest = "HDC411.html";
        break;
      case "HD200":
      case "HD400":
      case "HD500":
        dest = "HDF-1.html";
        break;
      case "":
      case "HD03W":
      case "HD04W":
      case "HD750":
      case "HD850":
        dest = "HDC-3T.html";
        break;
      case "MA0800":
        dest = "MAF-2.html";
        break;
      default:
        return;
    }
    if (dest != "")
      document.location.replace("/filters/" + dest + "?f=" + filter );

  }
  function selectFilter()
  {
    var s = document.location.toString();
    var i = s.indexOf("?f=");
    if (i == -1) 
      return;

    s = s.substring(i + 3);
    for (i=0; i<document.modelform.model.options.length; i++)
    {
      if (document.modelform.model.options[i].value == s)
      {
        document.modelform.model.options[i].selected = true;
        return;
      }
    }
    
  }