function diary_group_join(id) {
    new Ajax.Request('/groups/'+id+'/?action=join', {
        onComplete: function(t) {
            window.location = window.location;
        }
    });
}

function diary_group_leave(id) {
    new Ajax.Request('/groups/'+id+'/?action=leave', {
        onComplete: function(t) {
            window.location = window.location;
        }
    });
}