google.setOnLoadCallback(function() {
    jQuery.get(
        '/calendar/calendar.php',
        null,
        function(response){
            jQuery('#cal').html(response);
        }
    );
});

function cal(ym) {
    jQuery.get(
        '/calendar/calendar.php?ym=' + ym,
        null,
        function(response){
            jQuery('#cal').html(response);
        }
    );
}