$ _POST将不会收到Ajax

AJAX works fine, but $_POST does not have a value.

What I have tried:

• $data = json_decode(file_get_contents('php://input'), true); & $post = json_decode($data); into storecart.php
• Changing the data into 'jCart=' + jData'
• removing datatype (Jaromanda X)
• answer (Umakant Mane)

cart is an array of objects

Javascript:

        $(document).ready(function(){
            $("#showcart").click(function(event){
                event.preventDefault();
                showcart();
                url = 'cart.php';
                $(location).attr("href",url);
            });
        });

        function showcart(){
            var jData = JSON.stringify(cart);
            $.ajax({
                url:"storecart.php",
                type:"post",
                data: {jCart : jData},
                datatype: "json",
                success: function(data){
                    console.log("SUCCESS")
                    console.log(jData);
                },
                error: function(data){
                    console.log("REDO")
                }
            });     
        }

storecart.php:

<?php
    if(isset($_POST['jCart'])){
        echo "Right";
    }else{
        echo "Wrong";
    }
?>

How do get the $_POST to accept the json.stringify?

SOLUTION:

SOLVED:

All i did was add a form that has a hidden value

<form id = "postform" action = "cart.php" method = "post">
  <input type = "hidden" id="obj" name="obj" val="">
  <input type = "submit" value = "Show Cart" id = "showcart">
</form>

In the Javascript:

$(document).ready(function(){
  $("#showcart").click(function(){
    var json = JSON.stringify(cart)
    $('#obj').val(json);
    $('#obj').submit();
  });
});

Thank you for everyone that has answered but hope this helps.

 $(document).ready(function(){
 var data = {one:"one", two:"two", three:"three"};
 var jsonData = JSON.stringify(data);
  $("#clickme").click(function() {
  $.ajax({
  url:"demo.php",
  type:"POST",
  data:{cart:jsonData},
  success:function(response){
      console.log(response);
  }, error:function(err) {
    console.log(err);
 }

 })
 }); 
 });

PHP

  <?php

 if(isset($_POST['cart'])){
    echo "Right";
  }else{
    echo "Wrong";
  }
?>