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

  nav_doku_on = new Image;
  nav_doku_on.src = 'fileadmin/templates/img/nav_doku_on.gif';
  nav_doku_off = new Image;
  nav_doku_off.src = 'fileadmin/templates/img/nav_doku_off.gif';     

  nav_sitemap_on = new Image;
  nav_sitemap_on.src = 'fileadmin/templates/img/nav_sitemap_on.gif';
  nav_sitemap_off = new Image;
  nav_sitemap_off.src = 'fileadmin/templates/img/nav_sitemap_off.gif';     

  nav_kontakt_on = new Image;
  nav_kontakt_on.src = 'fileadmin/templates/img/nav_kontakt_on.gif';
  nav_kontakt_off = new Image;
  nav_kontakt_off.src = 'fileadmin/templates/img/nav_kontakt_off.gif';     

  nav_impressum_on = new Image;
  nav_impressum_on.src = 'fileadmin/templates/img/nav_impressum_on.gif';
  nav_impressum_off = new Image;
  nav_impressum_off.src = 'fileadmin/templates/img/nav_impressum_off.gif';     

  nav_presse_on = new Image;
  nav_presse_on.src = 'fileadmin/templates/img/nav_presse_on.gif';
  nav_presse_off = new Image;
  nav_presse_off.src = 'fileadmin/templates/img/nav_presse_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;
  }
}