Been there done that! More than once!! I couldn't even tell you how many times. Really sucks when you've just spent 4 hours doing a project in on-line class, and it all disappears. Save to Word file, and save often, works very well. Word also affords you the ability to spell check while composing your draft.
Unfortunately however, in doing web work, that method sometimes carries Word formatting into your HTML document and causes things to wig out. If you run into any problems doing that, drop the document into a notepad, or wordpad file before pasting to the web, and that will remove all formatting. Or, simply do a "Save As" on your file, and select "Plain Text" format from the menu, before pasting to the web.