The introduction of spl_autoload_register() gave programmers
the ability to create an autoload chain,
a series of functions that can be called to try and load a class or interface.
For example:
<?php
function autoloadModel($className) { $filename = "models/" . $className . ".php"; if (is_readable($filename)) { require $filename; }
}
function autoloadController($className) { $filename = "controllers/" . $className . ".php"; if (is_readable($filename)) { require $filename; }
}
spl_autoload_register("autoloadModel");
spl_autoload_register("autoloadController");