everyeurocounts on "Change php date array to javascript array"

I have a php array of dates ($fdates) which outputs as
array (size=1) 0 => string '2013/08/23' (length=10)

I need to change this to a Javascript array in this format

var array = ["2013-09-14","2013-09-15","2013-09-16"]

using json_encode i get ["2013V09V14"]

How do i change the format into the format above (its for beforedate in jquery date picker..

<?php
var_dump( $fdates ); // test query
echo json_encode($fdates);

?>
<script type="text/javascript">
var array = <?php echo json_encode($fdates); ?>;

jQuery(document).ready(function() {
    jQuery('#MyDate').datepicker({
		beforeShowDay: function(date){
        var string = jQuery.datepicker.formatDate('yy-mm-dd', date);
        return [ array.indexOf(string) == -1 ]
    }
    });
});

</script>