JavaScript & jQuery: The Missing Manual ... - Robert Guajardo

Adding jQuery to a
Page
I see that this book uses version 1.6.3 of jQuery, but the
current version on the jQuery site is 1.X. Is this a problem?
jQuery is always evolving. New bugs are often discovered,
and the jQuery team works diligently to fix them. In addition,
as new web browsers come out with new capabilities
and better support for current standards, the jQuery team
updates jQuery to work most efficiently with those browsers.
Finally, new features are sometimes added to jQuery to
make it more useful for web programmers. For these reasons,
it’s likely that you can find a newer version of jQuery
than the one that’s used in this book. If there is a newer
version, then by all means use it.
jQuery has matured over the years and its core functionality
changes very little. While the jQuery programmers
are often tinkering under the hood to make jQuery faster,
work better across browsers, and fix bugs, the way you
use jQuery doesn’t usually change that much. In other
words, while programmers might alter a jQuery function
to perform better, the way you use that function—the function
name, the arguments you give it, and the values it returns—don’t
often change. This means that what you learn
in this book will most probably work with a newer version
of jQuery, but only faster and better.
You can often tell how much different one version of
jQuery is from another by the numbering scheme. The first
number points to a very significant new version. Currently
FREQUENTLY ASKED QUESTION
jQuery Versions
Adding jQuery to a Page
122 javascript & jquery: the missing manual
jQuery is in version 1, so we’ve seen version 1, 1.2, 1.3, 1.4,
and so on. Version 2 (which probably won’t arrive for quite
some time) will undoubtedly offer some significant new
capabilities. Then there are the dot releases like the .6 in
jQuery 1.6. Each of those numbers usually offers new functions,
rewriting of older functions to work better, and so
on. Finally, the last number, like the final 3 in jQuery 1.6.3,
usually refers to some sort of bug fix for the 1.6 branch of
jQuery. So if you’re using version 1.6.3 of jQuery and version
1.6.8 comes out, it’s usually a good idea to upgrade, as
this will probably include fixes from problems discovered
in 1.6.3.
To find out what’s changed in a new version, just visit the
“Current release” section of the Downloads page at http://
docs.jquery.com/Downloading_jQuery#Current_Release.
There you’ll find a link to “Release notes.” Click that link
to visit a page listing changes made to that version. After
reading the list of changes, you can decide for yourself if it
seems worthwhile to upgrade (for example, if the changes
relate to features you don’t use on your site, you can probably
skip this upgrade; however, if the changes are bug
fixes related to features you do use, it’s a good idea to upgrade.
(If you use jQuery plug-ins on your site, you’ll need
to be a bit more cautious about upgrading to the latest
version of jQuery, unless you’re sure the plug-in works with
the new version of jQuery.)
If you’re using one of the CDN versions of jQuery (page 120), you can point to it using
one of the code snippets listed on page 120. For example, to use the Google CDN
version of jQuery, you’d add tags to the head of the page like this:
www.it-ebooks.info