function montreCacheSigne(what,what2,chemin)
{
 if ( document.getElementById(what).style.display == 'none' )
 {
  document.getElementById(what).style.display = '';
  document.getElementById(what2).src = chemin+"moins.gif";
 }
 else
 {
  document.getElementById(what).style.display = 'none';
  document.getElementById(what2).src = chemin+"plus.gif";
 }
}