function displayPart(/* elem to display*/ elemID)
{
  
  var class_name_link = "part_link";
  var class_name_page = "part_page";
  
  document.getElementById(elemID).style.display="block";
  
  // remise du scroll
  document.getElementById('cadre_content_middle').scrollTop='0px';
  
  
  // Tableaux pour les pages 
  part_pages = [];
  part_links = [];

  var content_page = document.getElementsByTagName("div"); 
  for (var i=0; i < content_page.length ; i++ )
  {
    elem = content_page[i];
        
      if (elem.className ==  class_name_page) 
      {
          part_pages.push(elem);
      }
  } 
    
  var content_link = document.getElementsByTagName("a");
  for (var i=0; i < content_link.length ; i++ )
  {
    elem = content_link[i];
      
    if (elem.className ==  class_name_link ||  elem.className ==  class_name_link+'_selected') 
    {
        part_links.push(elem);
    }
  }
 
  //alert(" bilan ->"+ part_pages.length  + "//"+ part_links.length );
  
  // affichage de la bonne page
  for (var i=0; i < part_pages.length ; i++ )
  {
    if (part_pages[i] !=  document.getElementById(elemID))
    part_pages[i].style.display='none';
  }
  
  // remise à zéro des autres backgrounds
  for (var i=0; i < part_links.length ; i++ )
  {
    if (part_links[i] !=  document.getElementById('link_'+elemID))
      part_links[i].className="part_link";
  } 
  
  // background du selectionné
    document.getElementById('link_'+elemID).className="part_link_selected";
}

function hide(/* elem to display*/ elemID)
{
  document.getElementById(elemID).style.display="none";
  /*part_'$name_part */
}