function filter_by(f, v)
{
  document.getElementById('fp_t').value=path_to;
  document.getElementById('ff').value=f;
  document.getElementById('fv').value=v;
  document.getElementById('filtfrm').submit();
}

function clear_filter(f)
{
  document.getElementById('fad').value='delete';
  document.getElementById('fp_t').value=path_to;
  document.getElementById('ff').value=f;
  document.getElementById('filtfrm').submit();
}