Here are the steps to take to enable JSON on PHP. These instructions are specific for Linux OS.
1. Install Pear
yum install php-pear
2. Install PHP-devel
yum install php-devel ; for phpize
3. Install json extension
pecl install json ;or
pear install json
4. Edit php.ini and add on extension list
extension=json.so
5. Save this and restart Apache
And you're done. You now have json enabled on your LAMP server.
Hope you find these useful. Thanks, CHeers and God Bless!!!!