Can comments be used in JSON?

Question

Can I use comments inside a JSON file? If so, how?

Answer 1

You can have comments in JSONP, but not in pure JSON. I've just spent an hour trying to make my program work with this example from Highcharts: http://www.highcharts.com/samples/data/jsonp.php?filename=aapl-c.json&callback=?

If you follow the link, you will see

?(/* AAPL historical OHLC data from the Google Finance API */
[
/* May 2006 */
[1147651200000,67.79],
[1147737600000,64.98],
...
[1368057600000,456.77],
[1368144000000,452.97]
]);

Since I had a similar file in my local folder, there were no issues with the Same-origin policy, so I decided to use pure JSON... and, of course, $.getJSON was failing silently because of the comments.

Eventually I just sent a manual HTTP request to the address above and realized that the content-type was text/javascript since, well, JSONP returns pure JavaScript. In this case comments are allowed. But my application returned content-type application/json, so I had to remove the comments.