frame_main = parent.main.location.href;
 frame_nav = parent.nav.location.href;

 if (frame_main.lastIndexOf("d/home.html")!=-1)
 {
  parent.nav.location.href = "../nav_home.html";
  parent.code.location.href = "../nav_home.html";
 }

 if (frame_main.lastIndexOf("d/100.html")==-1 && frame_nav.lastIndexOf("nav_home.html")!=-1)
 {
  parent.nav.location.href = "../nav.html";
  parent.code.location.href = "../nav_code.html";
 }