Efficient use of output buffer in PHP
Output Buffer is a process by which HTML or Javascript code or echo or print is produced in PHP with the information being sent to the browser and consequently to the web as an outcome. This is done by having the information stocked up on the server until the script is done executing, or by you doing something on the buffer itself.
To carry out this process, you should start the output buffer first. This should be done before anything else is fed to the browser. It is very important that you start it right after opening the PHP tag. You have to be very precise and sure that no prior action is done before the PHP tag is opened because even a lull or space can result to mistakes.