code: function() {
          if (this.textarea.element.form) {
            var hiddenField = document.createElement("input");
            hiddenField.type   = "hidden";
            hiddenField.name   = "_wysihtml5_mode";
            hiddenField.value  = 1;
            dom.insert(hiddenField).after(this.textarea.element);
          }
      }
docs: Creates hidden field which tells the server after submit, that the user used an wysiwyg editor