Learn Php

Php Constants

PHP constants are  identifiers for a simple values. Unlike variables  a constant value cannot change during the execution of the script. Constants are case-sensitive by default. By convention, constant identifiers are always uppercase. A constant name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. If you have defined a constant, it can never be changed or undefined. To define a constant you have to use define() function and to retri...

Php Predefined Variables

PHP  language has relatively  large number of predefined variables. Moreover an additional set of predefined arrays containing variables from the web server the environment, and user input. These new arrays are called SUPERGLOBALS Although many PHP frameworks provide abstractions over these superglobals, you still can access these variables as they are always  automatically available in all scopes, PHP SUPERGLOBALS Variable & Description $GLOBALS ...