$(function() {  //Get our elements for faster access and set overlay width  
    $("div.scrollVert").scrollable({ vertical: true, size: 2});
    // perform a simple API cal
});
function flecha(direccion) {
    var api2 = $("div.scrollVert").scrollable();
    if (direccion == 'up') {
       api2.prev()
    }
    else {
       api2.next()
    }
}