为什么PHP不能接收。。

 $.ajax({

       type: "POST",

        url: "index.php",

        data: "location=img_png_src",

        success: function(msg){

         alert( "Data Saved: " + msg );

           }

      });

<?php echo $_POST["location"]; ?>

PHP接受不了 报错了 Notice: Undefined index: location in C:\wamp\www\makebanner\index.php on line 45
------解决方案--------------------

<?php

if($_SERVER['REQUEST_METHOD'] == "POST") {

  print_r($_POST);

  exit();

}

?>

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.3/jquery.min.js"></script>

<script>

$(function() {

 $.ajax({

       type: "POST",

//        url: "index.php",

        data: "location=img_png_src",

        success: function(msg){

         alert( "Data Saved: " + msg );

           }

      });

});

</script>