PHP TutorialsPhp What is
PHP INI TutorialsPhp ini What is
This interesting directive tells PHP to pass all output through a function before returning it to the requesting user.
For example, suppose you want to compress all output before returning it to the browser, a feature supported by all mainstream HTTP/1.1-compliant browsers. You can assign output_handler like so:
ob_gzhandler() is PHP's compression - handler function, located in PHP's output control library.