如何格式化yy-mm-dd datepicker post到PHP？

Question

I have javascript jquery-ui datepicker library based function for selecting from_date - to_date range and post to php. Format is posted to php as:

Wed May 13 2015 00:00:00 GMT+0200 (Central European Summer Time)

How can I set format for example 2015-05-20 for datepicker post to php in my function?

       function updateResults() {
       $.getJSON('results.php', {
       from_date: fromDate.datepicker('getDate').toString(),
       to_date: toDate.datepicker('getDate').toString()
       }, function(data,status, xhr) {

       $.plot('#flotcontainer', data, options);
       });
       }


                            //create a couple of date textboxes
                    $.datepicker.setDefaults
                            ({
                                    dateFormat: 'dd/mm/yy', defaultDate: '-1w', changeMonth: true, changeYear: true,
                                    maxDate: 0, showButtonPanel: true, showWeek: true
                            });

                            var fromDate = $('#from').datepicker
                            ({
                                    onSelect: function()
                                    {
                                            var option = this.id == 'from' ? 'minDate': 'maxDate';
                                            toDate.not(this).datepicker('option', option, $(this).datepicker('getDate'));
            updateResults(); // When a new date is selected update the results

            }
                            });

                            var toDate = $('#to').datepicker
                            ({
                                    onSelect: function()
                                    {
            updateResults(); // When a new date is selected update the results


            }

                            });

                            //Set the default from and to dates.
                    fromDate.datepicker('setDate', '-1w');
                    toDate.datepicker('setDate', '+0');
                    updateResults(); // Initial call on load



              });

Answer 1

Format is posted to php as:

Wed May 13 2015 00:00:00 GMT+0200 (Central European Summer Time)

Make a timestamp from it first:

$ts = strtotime($_POST['date']);

How can I set format 2015-05-20 for datepicker post to php in my function?

With the timestamp, you can use date:

$date = date("Y-m-d", $ts);

Answer 2

You have to use $.datepicker.formatDate(); to convert dates.

Example:

var date = $('.datepicker').datepicker('getDate');
var convertedDate = $.datepicker.formatDate('dd-mm-yy', date);

So your function would become

function updateResults() {
    var from_date = fromDate.datepicker('getDate');
    var to_date = toDate.datepicker('getDate');

    from_date = $.datepicker.formatDate('yy-mm-dd', from_date);
    to_date = $.datepicker.formatDate('yy-mm-dd', to_date);

    $.getJSON('results.php', {
        from_date: from_date,
        to_date: to_date
    }, function (data, status, xhr) {
        $.plot('#flotcontainer', data, options);
    });
}

For a live example check this JSfiddle

EDIT:

Use $.datepicker.formatDate('yy-mm-dd', ..); to convert dates. I changed my answer and provided a JSfiddle