That being said, CM has taken steps to assist the members from losing the text they have typed by trying to catch when the browser attempts to leave the page prior to clicking the "Submit Post" button. It presents a dialog box as an opportunity to cancel moving to another page if it was unintended.
Several/Many Members have resorted to always typing their information in a text editor they are more comfortable with - then copying and pasting it from there to here when done. This method is not without its own woes though sometimes. Some programs use "curly quotes" and other special characters that will bee lost in the copy paste process t here. It is for this reason a very basic editor such as Notepad as opposed to MS Word might be better suited to ensure basic text and no loss of formatting. Other options for other operating systems exist also.
somewhere I had a very technical resposne to where the information (if it exists) is stored on a users local machine. If I can find it in a search of my posts, I will post a link to the thread if you are interested - but it is a bit technical - and chances are even if you find where it is stored - by now it is probably no longer there.
It goes into a bit more detail as to the various options and pitfalls you might run into
when composing a response here in the forums.