function show_cf() {
    if ($('contactform').getStyle('height')=='20px') {
    
        new Fx.Tween($('contactform'), {
            property: 'height',
            duration: 600
        }).start(20, 280);
        
        $('contactform_header_link').addClass('close');

    }
    else {
    
       new Fx.Tween($('contactform'), {
            property: 'height',
            duration: 600
        }).start(280, 20);
        
        $('contactform_header_link').removeClass('close');
    }            
}