无法在Javascript中解析PHP生成的JSON

I have a php script which returns a JSON string.

<?php
$arr = array(
'id' => '1',
'myarray' => array(
array('a' => 'a1', 'b' => 'b1', 'c' => 'c1', 'd' => 'd1'),
array('a' => 'a2', 'b' => 'b2', 'c' => 'c2', 'd' => 'd2')
)
);

echo json_encode($arr);
?>

The javascript code for parsing the JSON is

  $.ajax({
        dataType: "json",
        url: "http://www.something.com/sendJson.php"
    }).done(function(json) {
        data = jQuery.parseJSON(json);
        alert(data['id']);
    });

But for the above code i'm getting this error

SyntaxError: JSON Parse error: Unexpected identifier "object"

What could be causing this error?

The problem is your ajax call. You have dataType: "json", which means your string is already parsed in the callback. So:

 $.ajax({
    dataType: "json",
    url: "http://www.something.com/sendJson.php"
 }).done(function(json) {
    alert(json['id']);
 });