Uncaught SyntaxError: Unexpected token :
Seeing red errors
Uncaught SyntaxError: Unexpected token <
in your Chrome developer's console tab is an indication of HTML in the response body.
What you're actually seeing is your browser's reaction to the unexpected top line <!DOCTYPE html> from the server.
Just an FYI for people who might have the same problem -- I just had to make my server send back the JSON as application/json and the default jQuery handler worked fine.
This has just happened to me, and the reason was none of the reasons above. I was using the jQuery command getJSON and adding callback=? to use JSONP (as I needed to go cross-domain), and returning the JSON code {"foo":"bar"} and getting the error.
This is because I should have included the callback data, something like jQuery17209314005577471107_1335958194322({"foo":"bar"})
Here is the PHP code I used to achieve this, which degrades if JSON (without a callback) is used:
$ret['foo'] = "bar";finish();function finish() { header("content-type:application/json"); if ($_GET['callback']) { print $_GET['callback']."("; } print json_encode($GLOBALS['ret']); if ($_GET['callback']) { print ")"; } exit; }Hopefully that will help someone in the future.