将PHP-SQL Result变量转换为Javascript对象

I am making a simple web app, in one part of it, the result of SQL query is to be passed from PHP to JavaScript with AJAX.

This is the SQL Query:

$meta_query = mysql_fetch_row(mysql_query("SELECT * from meta WHERE user_id='$user_id'"));

This is how I pass it to JavaScript var_dump($meta_query);

This is what I am getting at JavaScript (as a string):

array(30) {[0]=>string(1) "3"["id"]=>string(1) "3"[1]=>string(2) "14"["user_id"]=>string(2) "14"[2]=>string(10) "29-06-2014"["date"]=>string(10) "29-06-2014"[3]=>string(1) "0"["present"]=>string(1) "0"[4]=>string(1) "0"["future"]=>string(1) "0"}

How, how do I convert this into a proper JavaScript object so that the output is something like:

{"id":"3","user_id":"14","date":"29-06-2014","Present":0,"Future":0}

How do I convert data from the first format to the second in JavaScript? Or should I do something else entirely in PHP to get the data out in some other format? Or should I convert the data to the required format somehow in PHP?

You might want to use

echo json_encode($meta_query);

from php side toy should convert php array to json object using
<?php echo json_encode($array)
here is tutorial how to do this

Don't forget to put in your jquery request dataType: "json"