php decode json object

$json = json_decode(file_get_contents('/path/to/your/file.json'));

$personJSON = '{"name":"Johny Carson","title":"CTO"}';

$person = json_decode($personJSON);

echo $person->name; // Johny Carson

<?php

$json = '{"firstName":"Peter","lastName:":"Silva","age":23}';

$personInfo = json_decode(json);

echo $personInfo->age;

?>

json_encode used when PHP retrieve data and convert Array() to [] !!!!
$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
echo json_encode($arr);
//output
{"a":1,"b":2,"c":3,"d":4,"e":5}
access from js file data.a, data.b,data.c...
----------------------------------------------
  $json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
json_decode($json, true); //true turns object to associative array;

//output
array(5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}