$(document).ready(function(){
    $('#clicky').click(function () {
    $.each(bgmp.markers, function(index, obj) {
        $.each(obj, function(key, value) {
            //window.alert(key+':'+value);
            if (key == 'visible') {
                //window.alert(obj['visible']);
                obj.setVisible(false);
                window.alert(obj['visible']);
            }
        });
    });
    });
});