spacer

Webref WebRef   Sitemap · Experts · Tools · Services · Newsletters · About i.com

home / experts / javascript / column42

The Document Object Model (DOM), Part III (5)

Developer News
News Flash: Adobe Has iPhone Workaround
Adobe's Flash 10.1 Goes Mobile (Minus iPhone)
A Salute to Visionary CEOs

Handling an Illegal HTML

Internet Explorer corrects automatically illegal HTML pages. An example for an illegal HTML construct is a list tag placed within a paragraph tag. In a valid HTML page, all lists should be positioned outside the page's paragraphs. Speaking in terms of the DOM's tree, it is illegal for a list node to be a grandchild of the body node. A list node should be a child of the body node. We chose to demonstrate an illegal HTML page with a specific list tag, the <UL> tag. Of course, the problem occurs for all types of lists: unordered (<UL>), ordered (<OL>), or descriptive (<DL>).

Let's take a simple example:

<HTML>
<HEAD>
<TITLE> DOM Demo </TITLE>
</HEAD>
<BODY ID="bodyNode">
<P ID = "p1Node">This is paragraph 1.
     <UL ID = "listNode">
          <LI ID = "bullet1Node">This is bullet 1
          <LI ID = "bullet2Node">This is bullet 2
          <LI ID = "bullet3Node">This is bullet 3
     </UL>
</P>
<P ID = "p2Node">This is paragraph 2.
</P>
</BODY>
</HTML>

Try to analyze this document example as is and sketch its DOM structure. Compare now with our own suggestion. Let's see now how Internet Explorer models this document in its DOM. The following script prints the top level children of the bodyNode node. Here are they:

bodyNode.firstChild.nodeName = P
bodyNode.childNodes[1].nodeName = UL
bodyNode.childNodes[2].nodeName = P
bodyNode.childNodes[3].nodeName = P

As you can see, the <UL> list tag is a child of the top level bodyNode tag node. This is not as it is appears in the original HTML page. The list is inside a paragraph and apparently should be a child of that <P> tag node. More than that, as you can see from the sketch of the corrected page implementation, the DOM presents three <P> tag nodes, while the document example above includes just two paragraphs. The browser corrects the illegal HTML page by splitting the culprit paragraph into two paragraphs: the first paragraph includes that portion of the original paragraph that precedes the list, while the second paragraph includes that portion of the paragraph that follows the list. In summary, we get an additional paragraph and a change in the list's position from a grandchild to a child of the bodyNode.

http://www.internet.com

Produced by Yehuda Shiran and Tomer Shiran

internet.commediabistro.comJusttechjobs.comGraphics.com

Search:

WebMediaBrands Corporate Info

Legal Notices, Licensing, Reprints, Permissions, Privacy Policy.
Advertise | Newsletters | Shopping | E-mail Offers | Freelance Jobs

Solutions

Whitepapers and eBooks

Adobe Article: Adobe Helps PHP Developers Create Rich Internet Applications
Adobe Article: Java Developers Finding a Home at Adobe Flex
IBM Articles: A Smarter Business Needs Smarter Technology
Intel Xeon Processor Increases Server Efficiency and Capabilities
Intel Tech Brief: Automated Energy Efficiency for the Intelligent Enterprise
Oracle Whitepaper: Using Oracle In-Memory Database Cache to Accelerate the Oracle Database
Oracle Whitepapers - Innovation for IT Leaders
Avaya Article: Communication-Enabled Mashups--Empowering Both Business Owners and IT
 Internet.com eBook: IT Manager's Guide to Social Networking
Internet.com eBook: Get Ready for Windows 7
Microsoft Article: Expression Web 3--New Features for PHP Developers
Whitepapers: Manage Your Business Infrastracture with IBM
Whitepaper: Maximize Your Storage Investment with HP
Internet.com eBook: Becoming a Better Project Manager
Microsoft Article: Stress Free and Efficient Designer/Developer Collaboration
MORE WHITEPAPERS, EBOOKS, AND ARTICLES

Webcasts

Webcast: Connecting PHP to Microsoft Technologies
Video: Microsoft Partner Program Benefits
Video: Windows Azure Debugging Tips
SAP BusinessObjects Webcast: Unlock the Power of Reporting with Crystal Reports
 IBM Webcast: Speed Business Innovation with Reduced Cost and Risk
Video: Deploy Applications on Windows Azure
MORE WEBCASTS, PODCASTS, AND VIDEOS

Downloads and eKits

Downloads & Free Trials: Microsoft's New Efficiency Resource Center
Get the Windows 7 SDK
Free Trial: Red Gate SQL Backup Pro 6
 Iron Speed Designer Application Generator
MORE DOWNLOADS, EKITS, AND FREE TRIALS

Tutorials and Demos

Virtual Lab: Migrating PHP Applications
Enabling Web Slices and Accelerators with a PHP Site
Internet.com Hot List: Get the Inside Scoop on the Hottest IT and Developer Products
 All About Botnets
MORE TUTORIALS, DEMOS AND STEP-BY-STEP GUIDES
webref The latest from WebReference.com Browse >
Building a Banking Application Home Page with OOP · Mixing Scripting Languages · Review: phpFox, a Social Networking CMS with all the Bells and Whistles
Sitemap · Experts · Tools · Services · Email a Colleague · Contact FREE Newsletters > 
 The latest from internet.com
Enterprise 2.0: Social Networking in the Cloud · BroadSoft Marketplace Hastens Pace of Telephony Innovation · Review: HTC Hero for Sprint


Created: June 21, 1999
Revised: June 21, 1999

URL: http://www.webreference.com/js/column42/list.html