Web Design in a Nutshell, 3rd Edition

JavaScript Dos and Don’ts

As web professionals, we have a duty to make the user experience as positive as possible and make our sites both usable and accessible. We always need to consider how our choices as programmers impact our users. Not only should we not wield JavaScript maliciously, but we should take care to use it in such a way that a page or site can be used without it.

What? No JavaScript?!

There are many situations in which users may not have JavaScript turned on, even if their browser supports it. In many corporate environments, security concerns around web browsers have led to JavaScript being disabled. Also, several accessibility experts have advocated for users of assistive devices (such as screen readers) to disable JavaScript because of the massive amount of obtrusive JavaScript in use that makes it difficult for them to easily navigate and use the Web.

As with CSS, JavaScript should “degrade gracefully,” in other words, your scripts should be written in such a way that they know if they will be able to run or not and quietly fail if methods they make use of are not supported. It is also important, for many reasons, including accessibility, that your scripts be unobtrusive. This is easily tested by turning off JavaScript support entirely in your browser to make sure the page can still be used.

This is a topic that will be touched on several times throughout this chapter and the next, but we’ll begin by discussing how to use JavaScript in your pages.