Save on close tab option

[TonyM]

Folks,

Background

I recently had help developing a reset dirty flag on tiddlywikis

Using the bookmarklet

javascript:(function(){ $tw.saverHandler.numChanges = 0; $tw.saverHandler.updateDirtyStatus(); })();

This is great to indicate you don't care if a save is not done when closing a tab with tiddlywiki in it.

Now of course there are tiddlywiki's I do want to save, and most I am quite happy to do so. However some have autosave off so in my multi-tiddlywiki tab world closing my browser can still be a chore with are you sure you want to leave messages, I then save and try to close again.

Question?

Would it be possible to provide an option in tiddlywiki that a save is triggered when the tab attempts to close? 

Perhaps this is an issue of the browser rather than tiddlywiki but I do not know so I though I would ask.

Ideally a solution that works with the various file/folder and savers available would further improve interactions with tiddlywiki.

Regards

Tony