jquery keypress event for cmd+s AND ctrl+s

Using one of the examples from a previous question I have:

$(window).keypress(function(event) {
    if (!(event.which == 115 && event.ctrlKey) && !(event.which == 19)) return true;
    $("form input[name=save]").click();
    event.preventDefault();
    return false;
});

Is it also possible to change this to work for the Mac cmd key?

I have tried (!(event.which == 115 && (event.cmdKey || event.ctrlKey)) && !(event.which == 19)) but this didn't work.