// Add click handlers for buttons to show and hide modal popup on pageLoad
        function pageLoad() {
            $addHandler($get("btnCancelar"), 'click', btnCancelar_Click);
        }
        
        function btnCancelar_Click(ev) {
            ev.preventDefault();        
            var modalPopupBehavior = $find('programmaticModalPopupBehavior');
            modalPopupBehavior.hide();
        }