This does not work for me. I am using firefox 2.0.0.3. I found that if I capture the form.submit method and rewrite it with one that creates a submit button and simulates a click I can get this to work, but it seems a poor solution.

I saw that in the IE code you are storing the from.submit in a variable called form_submit. then rewriting the form.submit method to call syncToHidden. Then calling the form_submit method to submit the form. I tried this is firefox but couldn't get it to work

below is the code used in winIE.js

var form_submit;
    if(form!=null)
    {
        form_submit="form.submit;"

        form.submit=FormSubmit;
        form.attachEvent('onsubmit',FormHandleSubmit);
    }
   
    //form.submit
    function FormSubmit()
    {
        if(!IsContentLengthOK())
            return false;

        editor.SyncToHidden();
        return form_submit();
    }