Check if a variable is a specific class

is_a — Checks if the object is of this class or has this class as one of its parents

bool is_a ( object $object , string $class_name [, bool $allow_string = FALSE ] )

Example

class exampleClass{
        public function foo(){
                echo "FOO";
        }
}
 
$ex = new example();
if (!is_a($ex,"example")){
        echo "var ex is not a example Class";
}