// bottom navigation

document.writeln('<table width="500" border="0" cellpadding="0" cellspacing="0"><tr>');

  iB = Number(imgnum - 1);
  iF = Number(imgnum - 1 + 2);
  if( imgnum ==  1 ) { iB = Number(12); }
  if( imgnum == 12 ) { iF = Number(1); }
  document.writeln('<td align="center" width="33%"><a href="slideshow.html?imgnum=',iB,'&basin=',basin,'">');
  document.writeln('<b>\<\< Prev Image</b></a></td>'); 

  document.writeln('<td align="center" width="33%">',JPG,'</td>');

  document.writeln('<td align="center" width="33%"><a href="slideshow.html?imgnum=',iF,'&basin=',basin,'">');
  document.writeln('<b>Next Image >></b></a></td>');

document.writeln('</tr></table>');