Why Ajax Post not working in Mozilla Firefox for PHP

Question

I have a site where when the page load it should he hit a php file. I am using following code of jquery ajax to pass data on php file that give me some response. but it return nothing in Mozilla. But its workes perfect in IE and Chrome Brwser. Any one can help me?

   <script>
        window.onload = MyFunction;

        var myString = "NO";

        function MyFunction2() {   // this function will be call on button click
            // alert("button clicked");
            myString = "Yes";

            $("#myModal").removeClass("in");
            $("#myModal").removeClass("fade");
            $(".modal-backdrop").remove();
            $("#myModal").hide();

            $('#myfadeDiv').removeClass('in');
            $('#myfadeDiv').removeClass('fade');
            $('#myfadeDiv').removeClass('modal-backdrop');

            MyFunction();
            location.href = 'http://www.MyExampleWebsite.com/';
        }



        // function submitQuery() {
        function MyFunction() {
            $.ajax({
                type: "POST",
                data: ({ result: myString }),
                url: "http://www.MyExampleWebsite.com/try.php",
                success: function (html) {
                    if (html == "  ") {
                        debugger;

                        $("#myModal").css("display", "block");
                        $('#myModal').addClass('in');
                        $('#myModal').addClass('fade');
                        $("#myModal").show();

                        $('#myfadeDiv').addClass('in');
                        $('#myfadeDiv').addClass('fade');
                        $('#myfadeDiv').addClass('modal-backdrop');
                    }
                    else {
                        debugger;
                        $("#myModal").removeClass("in");
                        $("#myModal").removeClass("fade");
                        $(".modal-backdrop").remove();
                        $("#myModal").hide();

                        $('#myfadeDiv').removeClass('in');
                        $('#myfadeDiv').removeClass('fade');
                        $('#myfadeDiv').removeClass('modal-backdrop');
                    }
                }
            });
            return false;
        }

        function closewindow() {
            if (confirm("Thank You. You May Close The Window.")) {
               // close();
                window.top.close();
                window.parent.close();
                var win = window.open("", "_self"); /* url = “” or “about:blank”; target=”_self” */
                win.close();
                window.close();
            }
        }
    </script>

try.php

<?php header('Access-Control-Allow-Origin: *');

   session_start();

   $msg2 = $_POST['result'];

   if($msg2=='Yes')
   {
   //session_start();


   if( isset( $_SESSION['counter'] ) ) {
      $_SESSION['counter'] += 1;
   }else {
      $_SESSION['counter'] = 0;
   }
    }
   $msg = $_SESSION['counter'];



?>
 <?php  echo ( $msg ); ?>