if(document.images) 
{    
  home_on = new Image;
  home_on.src = 'fileadmin/templates/img/home_on.gif';
  home_off = new Image;
  home_off.src = 'fileadmin/templates/img/home_off.gif';     

  sitemap_on = new Image;
  sitemap_on.src = 'fileadmin/templates/img/sitemap_on.gif';
  sitemap_off = new Image;
  sitemap_off.src = 'fileadmin/templates/img/sitemap_off.gif';     

  kontakt_on = new Image;
  kontakt_on.src = 'fileadmin/templates/img/kontakt_on.gif';
  kontakt_off = new Image;
  kontakt_off.src = 'fileadmin/templates/img/kontakt_off.gif';     

  impressum_on = new Image;
  impressum_on.src = 'fileadmin/templates/img/impressum_on.gif';
  impressum_off = new Image;
  impressum_off.src = 'fileadmin/templates/img/impressum_off.gif';     

  presse_on = new Image;
  presse_on.src = 'fileadmin/templates/img/presse_on.gif';
  presse_off = new Image;
  presse_off.src = 'fileadmin/templates/img/presse_off.gif';     

  nav_obs_on = new Image;
  nav_obs_on.src = 'fileadmin/templates/img/nav_obs_on.gif';
  nav_obs_off = new Image;
  nav_obs_off.src = 'fileadmin/templates/img/nav_obs_off.gif';     

  nav_wissenschaft_on = new Image;
  nav_wissenschaft_on.src = 'fileadmin/templates/img/nav_wissenschaft_on.gif';
  nav_wissenschaft_off = new Image;
  nav_wissenschaft_off.src = 'fileadmin/templates/img/nav_wissenschaft_off.gif';     

  nav_publikationen_on = new Image;
  nav_publikationen_on.src = 'fileadmin/templates/img/nav_publikationen_on.gif';
  nav_publikationen_off = new Image;
  nav_publikationen_off.src = 'fileadmin/templates/img/nav_publikationen_off.gif';     

  nav_veranstaltungen_on = new Image;
  nav_veranstaltungen_on.src = 'fileadmin/templates/img/nav_veranstaltungen_on.gif';
  nav_veranstaltungen_off = new Image;
  nav_veranstaltungen_off.src = 'fileadmin/templates/img/nav_veranstaltungen_off.gif';     
}

function imgAct(img_name)
{
  if(document.images) {
    img_on = eval(img_name + '_on.src');      
	  document.getElementById(img_name).src = img_on;
  }
}

function imgInact(img_name)
{
  if(document.images) {
    img_off = eval(img_name + '_off.src');          
    document.getElementById(img_name).src = img_off;
  }
}