restructured last chapters

chapter9/ch9-domflow.html

@@ -26,7 +26,7 @@
       }
       let divs = document.getElementsByTagName("div");
       for (let i = 0; i < divs.length; i++) {
-        divs[i].addEventListener("click", bup, true);
+        divs[i].addEventListener("click", bup);
       }
     </script>
   </body>