PHP has a single type operator: instanceof is used to
determine whether a given object, his parents or their implemented interfaces are of a specified
object class.
The instanceof operator was introduced in PHP 5.
Before this time is_a() was used but
is_a() has since been deprecated in favor of
instanceof.
<?php class A { } class B { }
$thing = new A;
if ($thing instanceof A) { echo 'A'; } if ($thing instanceof B) { echo 'B'; } ?>
As $thing is an object of type A, but
not B, only the block dependent on the A type will be executed:
