before posting anything 'ctrl A' 'ctrl C' then if it is lost, click on the reply again, and 'ctrl z'
My browser is Chrome, perhaps that makes a difference. (when you get the 'page cannto be displayed' perhaps clicking on reload at that point - if you get 'confirm form resubmission' at that point, I believe it may work. It also suggests an issue locally (ie your computer/browser - I dont know enough about computers to say what). If it simply says 'cannot display' everytime, it is a problem with your connection dropping out, I think.
![shrug](images/smilies/shrug.gif)