While writing, I try to save like I'm playing a Sierra adventure game. It would be nice to be able to save the chapter without going to the viewing page, so I don't lose my flow. I admit it's a little petty, but I figured I might as well suggest it anyway.
I usually click Save and then hit the back button of the browser. (In the beginning, I was even tempted to hit CTRL+S )
That's a good idea, but I'm a little worried that my browser will for some reason load the text from when I started writing that day (stupid I know) and I won't notice until I hit save, and I don't know if it works when creating a new chapter. (I don't think creating a chapter and editing it are the same web page.)
If you do that with a new chapter, you indeed might end up with several chapters. For editing chapters, you can try and see what happens. I especially use this for editing as I want to see the final version including formatting. So one tab shows the chapter as is and the second one is on the editing page. Reading on the one tab, then editing on the other one. Save. Back button. Back to the first tab. Refresh. That way I don't have to search the current position as the browser doesn't scroll to the top.
