将json文件发布到PHP

I am trying to pass a json file to PHP using Jquery. when I check the response I get the error json_decode expects parameter 1 to be a string.

Here is my jquery routine

 $("#ProcessData").click(function(){ 
var cols = $("#tblGroup thead tr th").map(function(){ 
 return $(this).text(); }); 

var headers = cols; 

// Fetch the data from the table body 
var tableObject = $("#tblGroup tbody tr.tableClass").map(function(i){
 var row = {}; $(this).find('td').each(function(i){ 
 var rowName = headers[i]; 
row[rowName] = $(this).text(); 
}); 

return row; 

}).get(); 

// convert object to JSON 
JSON.stringify(tableObject); 

//now call ajax to pass info to php 

$.ajax({ 
url: 'php/ProcessOrder.php', 
data: {my_json_data: tableObject}, 
type: 'POST', 
async: false, 
dataType: 'json', cache:false 
}); 
});

here is my php script

<?PHP
//this is the layout of the json object
//Title:First Name:Surname:Group Name this will needamending as the json object builds

require("dbsettings.php");
$_Reference= $_POST["my_json_data"]; //this is a json object
// Loop through Array
$someArray = json_decode($_Reference, true); // Replace ... with your PHP Array

foreach ($someArray as $key => $value) {
 echo $value["Title"] . ", " . $value["First Name"] . ", " . $value["Surname"] . ", " . $value["Group Name"] . "<br>";
}

?>

here is my json object

{"Title":"Mr","First Name":"12","Surname":"12","Group Name":"as"}

Using php fiddle I created and tested this script which worked perfectly

<?php

$someJSON = '[{"name":"Jonathan Suh","gender":"male"},{"name":"William Philbin","gender":"male"},{"name":"Allison McKinnery","gender":"female"}]';


// Loop through Array
$someArray = json_decode($someJSON, true); // Replace ... with your PHP Array

foreach ($someArray as $key => $value) {
 echo $value["name"] . ", " . $value["gender"] . "<br>";
}

?>

One thing I did notice is my php fidle json file has [] the posted object doesn't is this what the error message refers too? Or Should I not JSON.stringfy() and just pass it as a string into php and use JSON_encode?

thanks for any assistance

The JSON.stringify returns the encoded string. You have to post its returned value, not the parameter passed to it.

// convert object to JSON 
json = JSON.stringify(tableObject); 

//now call ajax to pass info to php 

$.ajax({ 
url: 'php/ProcessOrder.php', 
data: {my_json_data: json}, 
type: 'POST', 
async: false, 
dataType: 'json', cache:false 
}); 
});