JSON not working in php script -

i'm not getting json_encode work in php file. instance, tried example got php.net

<?php $arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);  echo json_encode($arr); ?> 

but nothing works. if remove echo statement, php works, means php isn't recognizing json_encode code.

i'm using php 5.4.16. sum up, i'm using xampp 1.8.2.

help please?

it sounds there fatal error somewhere else in script. make sure display_errors set on in php.ini.