An alternative and perhaps less time-consuming method is the *show_password one:
You have just started Chapter 2. Do you want to restore a game?
*choice
#No
*goto regular_start
#Yes
*restore_password
*goto regular_start
*label regular_start
*show_password
Chapter 2: The Shugenja
What show_password does is display a large string you can copy, and later paste into the restore_password textbox. If you do this at the start of each chapter, players will be able to go back and make different choices etc. As long as players have those large strings of text saved somewhere, they can exit their browser and still get back to where they were with the same stats.
EDIT:
Forgot about this, but you’ll have to open up the index.html file (with notepad++ for example) in your mygame folder and look for:
<script src="../ui.js"></script>
<script src="../scene.js"></script>
<script src="../navigator.js"></script>
Beneath that, insert this:
<script>
Scene.validCommands["restore_password"] = 1;
</script>
This will allow you to use the restore_password command.