November 2001
Intermediate to advanced
936 pages
68h 43m
English
Content preview from JavaScript: The Definitive Guide, Fourth EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Using the Core DOM API
Now that we’ve studied the tree structure of documents and seen how the tree is composed of Node objects, we can move on to study the Node object and document trees in more detail. As I noted previously, the core DOM API is not terribly complex. The following sections contain examples that demonstrate how you can use it to accomplish common tasks.
Traversing a Document
As
we’ve already discussed, the DOM represents an HTML document as
a tree of Node objects. With any tree structure, one of the most
common things to do is traverse the tree, examining each node of the
tree in turn. Example 17-1 shows one way to do this.
It is a JavaScript function that recursively examines a node and all
its children, adding up the number of HTML tags (i.e., Element nodes)
it encounters in the course of the traversal. Note the use of the
childNodes
property of a node. The value of this
property is a NodeList object, which behaves (in JavaScript) like an
array of Node objects. Thus, the function can enumerate all the
children of a given node by looping through the elements of the
childNodes[] array. By recursing, the function
enumerates not just all children of a given node, but all nodes in
the tree of nodes. Note that this function also demonstrates the use
of the nodeType
property to determine the type of each
node.
Example 17-1. Traversing the nodes of a document
<head> <script> // This function is passed a DOM Node object and checks to see if that node // represents an ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.