Ajax将Json传递给PHP

Question

I have looked at a few post but cant seem to work out what I've done incorrect, i need to work with the JSON to inport into database but it saying my posted cities is not coming through?

Javascript

     console.log(jsonData);
      $.ajax({
          url: "ajax.php",
          type: "post",
          data: jsonData,
      datatype: 'json',
          success: function(jsonData){  

               $('#result').html(jsonData);

          },
          error:function(){
              alert('ajax failed');    
          }   
        }); 
}

Ajax.php

$obj = json_decode($_POST['cities']);

print_r($obj);

Error :

Notice: Undefined index: cities in ajax.php on line 3

Console Log for Json

{"currentCity":"Exeter","cities":[{"name":"Exeter","offers":[{"offer":"test","price":"11","notes":"100","city":"Exeter"}]}]}

Answer 1

Well firstly, datatype needs to be dataType. Note that this follows the lower camel case nomenclature.

Secondly, $_POST['cities']; will not work because it is the key in a JSON object and not a key to a post identifier. What you need to do is pass it along like, data: {'json' : jsonData}, then you can do:

 $obj = json_decode($_POST['json']);
 print_r($obj['cities']);

edit

So your ajax call will look like below:

$.ajax({
     url: "ajax.php",
     type: "post",
     data: {
         "json" : jsonData
     },
     dataType: 'json',
     success: function(jsonData){  
          $('#result').html(jsonData);
     },
     error:function(){
         alert('ajax failed');    
     }   
});