public function form_tag($attrib, $content = null)
    {
        if ($this->env['extwin']) {
            $hiddenfield = new html_hiddenfield(array('name' => '_extwin', 'value' => '1'));
            $hidden = $hiddenfield->show();
        }
        else if ($this->framed || $this->env['framed']) {
            $hiddenfield = new html_hiddenfield(array('name' => '_framed', 'value' => '1'));
            $hidden = $hiddenfield->show();
        }

        if (!$content) {
            $attrib['noclose'] = true;
        }

        return html::tag('form',
            $attrib + array('action' => $this->app->comm_path, 'method' => "get"),
            $hidden . $content,
            array('id','class','style','name','method','action','enctype','onsubmit')
        );
    }