T he most interesting page is subpage.htm. Although it is not a default page declared in the frameset, it will be opened within the frameset if we try to open it. Just close that window to return back here. C lick to open framespage.htm . It will open the frameset in the ordinary way.
C lick to open subpage.htm .
It will try to open subpage outside the frameset. As you will see, the script ensures that the page gets opened within the frameset instead.