Most forums and many websites (like gmail) are able to save your post in a cookie as you type. If you navigate away by mistake, the post will be waiting for you if you go right back.
Does the billion dollar forum have that feature? I got so used to it I forgot this forum is so old... :/
If you accidentally close the tab while creating a post just hit Ctrl+Shift+T and the tab will re-open with all your drafted posts still there if you hit the browser back you can still go back by hitting forward in the browser, in fact I experienced a power outage several times and when the power is back I still can see all my works there.
I think it has something to do with how you configure your browser I configure my browser to Continue where I left off so even if there's a power outage I can go back to my work with the tabs I left off opened, I seldom lose my draft post here in Bitcointalk, if you want to be sure just use what others are recommending and this is my saving your work in a draft if you're creating a long post.