It actually works for me as well if I run it in the browser. The structure of the app is a bit strange, though, so debugging character encoding issues is quite difficult. The code is being run by Code Igniter in the backend and the response passed via JSON to a ExtJS 4 frontend, so what I'm looking at to debug is the server's response in the browser console. What I can say is that I decode the string and pass it immediately afterwards to the EvalMath class that was suggested earlier, it complains that there's illegal characters "<", so obviously it's the server that isn't operating as expected... but why? PHP/5.3.2-1ubuntu4.14 Apache/2.2.14 -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php