function choices()
{
//elegir el numero de banner que se desean insertar, ej: 8
this[0] = 1;

// PRIMER BANNER, Tradedoubler Casa del libro 250x250
this[1] = '<script type="text/javascript" src="http://impes.tradedoubler.com/imp?g(16318174)a(917862)" charset="ISO-8859-1"></script>';

// SEGUNDO BANNER, Tradedoubler Círculo de lectores 250x250
this[2] = '<script type="text/javascript" src="http://impes.tradedoubler.com/imp?g(16866308)a(287784)" charset="ISO-8859-1"></script>';


//si se pone arriba ej: 7 aqui añadir this[7]=' codigo ';
}
function popUpBanner(list)
{
var today = new Date();
var choiceInstance = new choices();
var Banner = choiceInstance[(today.getSeconds() % choiceInstance[0]) + 1];
}
function grabBanner()
{
var today = new Date();
var choiceInstance = new choices();
var Banner = choiceInstance[(today.getSeconds() % choiceInstance[0]) + 1];
return Banner;
}
document.writeln(grabBanner());