PHP TutorialsPhp What is
PHP INI TutorialsPhp ini What is
The include() statement will evaluate and include a file into the location where it is called. Including a file produces the same result as copying the data from the file specified into the location in which the statement appears.
Like the print and echo statements, you have the option of omitting the parentheses when using include().
if you want to include a series of predefined functions and configuration variables, you could place them into a separate file(called init.inc.php, for example), and then include that file within the top of each PHP script.