php - How do I enable cross-origin resource sharing on XAMPP?

Question

I have a html file on my localhost with a form and jquery/ajax which handles the post data. A simple php script looks up the data in a mysql database table

This is the main part:

// $.post('lookup_update.php', $(this).serialize()) //<- local part which works
   $.post('http://www.example.com/projectX/lookup_update.php', $(this).serialize()).done(function (data)
                            { etc.

But when I point to the online lookup_update.php I get the following error message in chrome

XMLHttpRequest cannot load http://www.example.com/projectX/lookup_update.php. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost' is therefore not allowed access. The response had HTTP status code 404.

As I understand it I need to use

 header("Access-Control-Allow-Origin: *");

for php. But when I add this to example.com/lookup_update.php, the file gives a 404 when the localhost file tries to call it.

I also tried to add the following to my Xampp apache config file

Header set Access-Control-Allow-Origin "*"

How do I correctly enable cross-origin resource from my local XAMPP setup??

[EDIT] This is my simple form on my localhost

<!--Begin form-->
    <div id="form" class="result">
        <form method="post" id="reg-form"  class="form-horizontal">
            <div class="controls">
                <input type="text" name="code" id="code" placeholder="Code"  class="form-control input-lg" />      
            </div>
        </form>
    </div>
    <!--End form-->

With the following form jquery code

    <script type="text/javascript">
            $(document).ready(function ()
            {
                $(document).on('submit', '#reg-form', function ()
                {
                    var tmpCode = $("#code").val();

//                    $.post('lookup_update.php', $(this).serialize())
                      $.post('http://www.example.com/projectX/lookup_update.php', $(this).serialize())
                            .done(function (data)
                            {

                                $("#reg-form").fadeOut('slow', function ()
                                {
                                    $(".result").fadeIn('slow', function ()
                                    {
                                        console.log("inner test " + tmpCode);
                                        $(".result").html(data);


                                        setTimeout(function () {
                                            location.reload();
                                            $('input').val("");
                                        }, 3000);


                                    });
                                });
                            })
                            .fail(function ()
                            {
                                alert('fail to submit the data');
                            });
                    return false;
                });


            });

        </script>

[EDIT 2]

OK, i don't think it has to do with the online lookup_update.php file, as I am using this to test in another file

            var testXHR = $.post("http://www.example.com/projectX/lookup_update.php", function (data) {
            alert("success:" + data);
        })

And in the alert popup window I see the expected data

Answer 1

You have to write below code at the beginning of your lookup_update.php

header('Access-Control-Allow-Origin: *');
header('Content-type: application/json');

Instead of * you can write just Ip address.

OR

First you have to check where is problem either on localhost or other server.

Try this code : If you getting some data in alert then problem is on localhost else on other server.

$.post( "test.php", function( data ) {
alert( "Data Loaded: " + data );
});