Warn user before closing tab with unsaved changes (e.g. Text in the textbox which was not submitted yet)

Hi all,

I just stumbled upon the following idea:

• Auto save for long topics/posts/replies Open
• 14 Votes

I have an idea for the same problem, but with a different (possibly simpler?) solution

The Problem.

Scenario: some of our users (and esp. our moderators) are writing a well thought-out reply in the text box. They take a small break (slack notification, or they need to do research before completing the reply) and then accidentally close the tab and lose everything. Problem is that there is no warning before closing the tab.
They then have to type the whole comment again, often with lots of frustration. 

Our current workaround.

Whenever I write a reply, i have taken the habit to Ctrl+A & Ctrl+C  the heck out of it, just to make sure the content is at least in my clipboard. in some instances, I also copy that text into my slack textbox so I know it’s really safe. We admins know this workaround (which isn’t the most pleasant one esp. if we have to do it every time) but it’s not really something that we wanna broadcast to the whole community. “Hey btw, you might lose your WIP comments if you’re unlucky, so make sure to always safeguard your reply somewhere!” 
BTW: This also applies to topics, not only replies.

Proposed solutions.

Either an autosave function just like @m4rc suggested above.
OR

What would be good enough is a kind of browser pop-up before closing the tab or the window, to prevent the tab from closing. So if you close the tab by accident,  you click on cancel and you’re back to your in-progress comment.
Other sites/forums also have this and it’s saved me lots of frustration.

1. @inSided, would you consider releasing this feature?
2. Otherwise, is this  something that I can already implement manually with some sort of third-party script?

Thanks for coming to my TED Talk!
Happy holidays, 
Daniele