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jQuery in Action - Manning Publications

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<strong>jQuery</strong> fundamentals<br />

That’s another use of the $() function; now let’s look at yet someth<strong>in</strong>g else it can<br />

do for us.<br />

1.3.4 Mak<strong>in</strong>g DOM elements<br />

As you can see by now, the authors of <strong>jQuery</strong> avoided <strong>in</strong>troduc<strong>in</strong>g a bunch of global<br />

names <strong>in</strong>to the JavaScript namespace by mak<strong>in</strong>g the $() function (which you’ll recall<br />

is merely an alias for the <strong>jQuery</strong>() function) versatile enough to perform many<br />

duties. Well, there’s one more duty that we need to exam<strong>in</strong>e.<br />

We can create DOM elements on the fly by pass<strong>in</strong>g the $() function a str<strong>in</strong>g that<br />

conta<strong>in</strong>s the HTML markup for those elements. For example, we can create a new<br />

paragraph element as follows:<br />

$("Hi there!")<br />

But creat<strong>in</strong>g a disembodied DOM element (or hierarchy of elements) isn’t all that useful;<br />

usually the element hierarchy created by such a call is then operated on us<strong>in</strong>g one<br />

of <strong>jQuery</strong>’s DOM manipulation functions. Let’s exam<strong>in</strong>e the code of list<strong>in</strong>g 1.1 as an<br />

example.<br />

List<strong>in</strong>g 1.1 Creat<strong>in</strong>g HTML elements on the fly<br />

<br />

<br />

Follow me!<br />

<br />

<br />

<br />

<br />

$(function(){<br />

$("Hi there!").<strong>in</strong>sertAfter("#followMe");<br />

});<br />

<br />

<br />

<br />

Follow me!<br />

<br />

<br />

This example establishes an exist<strong>in</strong>g HTML paragraph element named followMe C <strong>in</strong><br />

the document body. In the script element with<strong>in</strong> the section, we establish a<br />

ready handler B that uses the follow<strong>in</strong>g statement to <strong>in</strong>sert a newly created paragraph<br />

<strong>in</strong>to the DOM tree after the exist<strong>in</strong>g element:<br />

$("Hi there!").<strong>in</strong>sertAfter("#followMe");<br />

The result is shown <strong>in</strong> figure 1.3.<br />

We’ll be <strong>in</strong>vestigat<strong>in</strong>g the full set of DOM manipulation functions <strong>in</strong> chapter 3,<br />

where we’ll see that <strong>jQuery</strong> provides many means to manipulate the DOM to create<br />

nearly any structure that we may desire.<br />

B<br />

C<br />

Ready handler that<br />

creates HTML element<br />

Exist<strong>in</strong>g element<br />

to be followed<br />

13

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