function js_iniciar_video()
{
 new PeriodicalExecuter(js_video,7);
}
function js_video()
{
 var destino = $('principal_video');
 if (!destino) return false;
 var params = Form.serialize($('form_video'));
 new Ajax.Updater(destino, 'js/aqm_video.php', {asynchronous:true, parameters:params});
}