To harness or exploit the most out of CSS classes is to take advantage of what truly is the unsung hero of advanced RIA development as it relates to the presentation layer. When we observe our markup, we find that various portions of the DOM may require styling influences on the initial page load as well as interaction events or cues to adjust its structure, positioning, visibility, state, and skin. For this classes are the clear suitor, as it brings flexibility, modularity, inheritance, and a dynamic and unobtrusive nature to the table.

It is still a controversial issue today despite the recent evolutions in the industry including new modern browsers and new resources such as jQuery (as of version 1.3) that now entirely base their implementations on feature testing. However, somehow the practice of browser detection seems to still be alive and well, whether it be new browsers bringing about new bugs, features that are difficult to detect, or simply shortcuts spawned out of pure laziness, the practice is not only being used but defended. Browser sniffing can be found around just about every corner you look – from the smallest of websites, to your favourite JavaScript library (Mootools, Prototype, YUI, etc.) utilized in corporate giants such as Chrysler, Gamespot, and Yahoo!

It is rarely even a question anymore; deciding whether to use a JavaScript library on your next project typically goes without saying, the real question developers find themselves asking is which library should it be? However the decision to adopt any framework for a project should not be taken lightly and deserves a proper evaluation of requirements before making a decision based on assumptions. Often a library may ask of a developer, “Does the JavaScript library help me to write JavaScript?”, but shouldn’t they ask if the library helps them to learn JavaScript? Learning the syntax of your favourite JavaScript library does nothing for the developer’s understanding of the language itself or the impact on performance, memory, and reliability of their implementations. For this article, I will be looking at both sides of the argument, but hiding my bias will not be easy, my hope here is that perhaps a few developer’s may rethink their approach.

Scope or context as it is often referred to as is one of the fundamental aspects of Javascript, playing a significant role unlike that of any other language. Scope refers to the accessibility of variables and its execution context which belongs to the object or function in which it was defined. However this does not always hold true as scope can be lost or changed depending on how and where it used, specifically as it applies to functional execution.