One of the most widely used design patterns in JavaScript is the module pattern. The module pattern makes use of one of the nicer features of JavaScript – closures – in order to give you some control of the privacy of your methods so that third party applications cannot access private data or overwrite it. In this post I’ll teach you what a closure is, how it works, and how to utilize it to implement the module pattern in your own JavaScript code.
The Command Pattern is a strange beast in the context of object-oriented programming. Unlike most objects, a command object represents a verb, rather than a noun. This is a little less odd in a language like JavaScript where functions are actually a type of object, but the classical sense of the Command pattern is still different than a function.
This is the first in what should be a pretty long series about JavaScript design patterns. In 1995, Erich Game, Richard Helm, Ralph Johnson and John Vlissides (known as the Gang of Four) published Design Patterns: Elements of Reusable Object-Oriented Software, a book cataloging recurring solutions to common dilemmas in software architecture and design. It also started a common vocabulary for referring to these solutions. If you’d like to know more you can find it on Wikipedia.
The ProblemCross-site Scripting is a problem in the world of the internet. Someone hijacks your web site by injecting a little bit of JavaScript code and suddenly he/she has access to pretty much anything they want on your site. Douglas Crockford gave a talk at the end of March last year (at least, that’s when his video was published on YUI Theater) that partially discussed this problem, and this article is largely based off that talk. He noted the web’s vulnerabilities to these types of attacks, mostly due to standards that must be implemented by the browsers and having very little to do with bugs. He also felt, though, that JavaScript is one the best languages for creating secure code.