I have issue too.

my code not work and i can't see errors..

where I can download jsonRPCClient.php ?

I checked server error.log:

Code:

PHP Fatal error: Class 'jsonRPCClient' not found in /var/www/html/index.php on line 4

but I use include_once('jsonRPCClient.php');

Thanks.

The link available at https://en.bitcoin.it/wiki/API_reference_(JSON-RPC)#PHP doesn't seem to be working.
You can try with EasyBitcoin-PHP available at https://github.com/aceat64/EasyBitcoin-PHP