ok so far these are the subjects or sections or whatever its called about php that i know of. or sections of study
PHP & mysql interaction with the browser
PHP & xml
setting .htacess rules(not php but something to know)
then maybe php security(guarding against xss and injection)
what are other sections of study for php because once i master the above does it mean i know php and i can go forward and create whatever comes to mind, and occasionally look at php.net for new functions i can take use of?