JQuery_ Novice to Ninja - Earle Castledine [5]
In the following chapter we’ll have a look at what makes jQuery so good, and how it complements HTML and CSS in a more natural way than our old friend and bitter enemy: plain old JavaScript. We’ll also look at what’s required to get jQuery up and running, and working with our current sites.
What’s so good about jQuery?
You’ve read that jQuery makes it easy to play with the DOM, add effects, and execute Ajax requests, but what makes it better than, say, writing your own library, or using one of the other (also excellent) JavaScript libraries out there?
First off, did we mention that jQuery makes it easy to play with the DOM, add effects, and execute Ajax requests? In fact, it makes it so easy that it’s downright good, nerdy fun—and you’ll often need to pull back from some craziness you just invented, put on your web designer hat, and exercise a little bit of restraint (ah, the cool things we could create if good taste were not a barrier!). But there are a multitude of notable factors you should consider if you’re going to invest your valuable time in learning a JavaScript library.
Cross-browser Compatibility
Aside from being a joy to use, one of the biggest benefits of jQuery is that it handles a lot of infuriating cross-browser issues for you. Anyone who has written serious JavaScript in the past can attest that cross-browser inconsistencies will drive you mad. For example, a design that renders perfectly in Mozilla Firefox and Internet Explorer 8 just falls apart in Internet Explorer 7, or an interface component you’ve spent days handcrafting works beautifully in all major browsers except Opera on Linux. And the client just happens to use Opera on Linux. These types of issues are never easy to track down, and even harder to completely eradicate.
Even when cross-browser problems are relatively simple to handle, you always need to maintain a mental knowledge bank of them. When it’s 11:00 p.m. the night before a major project launch, you can only hope you recall why there’s a weird padding bug on a browser you forgot to test!
The jQuery team is keenly aware of cross-browser issues, and more importantly they understand why these issues occur. They have written this knowledge into the library—so jQuery works around the caveats for you. Most of the code you write will run exactly the same on all the major browsers, including everybody’s favorite little troublemaker: Internet Explorer 6.
This feature alone will save the average developer a lifetime of headaches. Of course, you should always aim to keep up to date with the latest developments and best practices in our industry—but leaving the task of hunting down obscure browser bugs to the jQuery Team (and they fix more and more with each new version) allows you more time to implement your ideas.
CSS3 Selectors
Making today’s technologies cross-browser compliant is all well and good, but jQuery also fully supports the upcoming CSS3 selector specification. Yes, even in Internet Explorer 6.0! You can gain a head start on the future by learning and using CSS3 selectors right now in your production code. Selecting elements you want to change lies at the heart of jQuery’s power, and CSS3 selectors give you even more tools to work with.
Helpful Utilities
Also included is an assortment of utility functions that implement common functions useful for writing jQuery (or are missing from JavaScript!): string trimming, the ability to easily extend objects, and more. These functions by themselves are particularly handy, but they help promote a seamless integration between jQuery and JavaScript which results in code that’s easier to write and maintain.
One noteworthy utility is the supports function, which tests to find certain features are available on the current user’s browser.