var nav_showcaseoverview_off = new Image();
  nav_showcaseoverview_off.src = "/images/nav_showcaseoverview_off.gif";
  var nav_showcaseoverview_over = new Image();
  nav_showcaseoverview_over.src = "/images/nav_showcaseoverview_over.gif";

  var nav_runningonbasis_off = new Image();
  nav_runningonbasis_off.src = "/images/nav_runningonbasis_off.gif";
  var nav_runningonbasis_over = new Image();
  nav_runningonbasis_over.src = "/images/nav_runningonbasis_over.gif";

  var nav_successstories_off = new Image();
  nav_successstories_off.src = "/images/nav_successstories_off.gif";
  var nav_successstories_over = new Image();
  nav_successstories_over.src = "/images/nav_successstories_over.gif";

  var nav_appdirser_off = new Image();
  nav_appdirser_off.src = "/images/nav_appdirser_off.gif";
  var nav_appdirser_over = new Image();
  nav_appdirser_over.src = "/images/nav_appdirser_over.gif";