form.py 文件源码

def hidden_tag(self, *fields):
        """Render the form's hidden fields in one call.

        A field is considered hidden if it uses the
        :class:`~wtforms.widgets.HiddenInput` widget.

        If ``fields`` are given, only render the given fields that
        are hidden.  If a string is passed, render the field with that
        name if it exists.

        .. versionchanged:: 0.13

           No longer wraps inputs in hidden div.
           This is valid HTML 5.

        .. versionchanged:: 0.13

           Skip passed fields that aren't hidden.
           Skip passed names that don't exist.
        """

        def hidden_fields(fields):
            for f in fields:
                if isinstance(f, string_types):
                    f = getattr(self, f, None)

                if f is None or not isinstance(f.widget, HiddenInput):
                    continue

                yield f

        return Markup(
            u'\n'.join(text_type(f) for f in hidden_fields(fields or self))
        )