Json array object undefined value

Question

I'm trying to get an array of object from php with ajax request.

Until now all is ok, i get my array in json format in my ajax response in javascript {"ID:"9348","Name":"Mark"} .

But now if i try to get the object with alert(data["ID"])

 $.ajax({ url:'loaddata.php', dataType:'json', success:function(data){ alert(data['ID']); }, error: function (thrownError) { alert("errore"); } });

i get " undefined " Can anybody help me ???

---

in my php file i have this:

 $a=array(); while($row = mysql_fetch_array($result,MYSQL_ASSOC)){ $a[] = json_encode (array('ID'=>$row['ID'],'name'=>$row['name'])); } header("Content-Type: application/json"); echo json_encode($a);

Answer 1

From the php code you posted it seems that you return an array. therefor you have to select the dataset by array index:

alert(data[0]['ID']);

and your json probably looks like this:

[ {"ID":"9348","Name":"Mark"}, ... ]

Answer 2

you are double encoding

in-loop: $a[] = json_encode (... // this makes $a an array of json-strings
outside: echo json_encode($a ... // this echos an JSON representation of an array of json-strings

this will not work, just produce/gather your array, then at the end do json_encode once

• unless you really want JSON-Strings inside your JSON-Object/Array