Correct OOP for Javascript. It is possible in Javascript (ECMAScript) to do classical single inheritance nested to any depth, without any caveats.
This article concisely explores the mechanism in depth, including flaws in other approaches, internal Javascript algorithms, proper OOP data encapsulation with default constructors, and an optimized inheritance declaration syntax with both Object and Function prototype convenience methods. by Shelby H. Moore III. Object-Oriented Features New To PHP5.
Peter Lavin This chapter is excerpted from Object-Oriented PHP: Concepts, Techniques, and Code from NoStarch Press.
PHP 3 was released in mid-1998. Some basic object-oriented (OO) capabilities were included, more or less as an afterthought, to "provide new ways of accessing arrays. "1 No significant changes were made to the object model when version 4 was released in mid-2000. The basics of object-oriented programming (OOP) were there--you could create a class and single inheritance was supported.
With the release of PHP 5 in 2004 there was plenty of room for improving PHP's OO capabilities.