Document Object Model
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The Document Object Model (DOM) is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML, and XML documents. The nodes of every document are organized in a tree structure, called the DOM tree. Objects in the DOM tree may be addressed and manipulated by using methods on the objects. The public interface of a DOM is specified in its application programming interface (API).
Legacy DOM was limited in the kinds of elements that could be accessed. Form, link and image elements could be referenced with a hierarchical name that began with the root document object. A hierarchical name could make use of either the names or the sequential index of the traversed elements. For example, a form input element could be accessed as either
The Legacy DOM enabled client-side form validation and the popular "rollover" effect.
After the release of ECMAScript, W3C began working on a standardized DOM. The initial DOM standard, known as "DOM Level 1", was recommended by W3C in late 1998. About the same time, Internet Explorer 5.0 shipped with limited support for DOM Level 1. DOM Level 1 provided a complete model for an entire HTML or XML document, including means to change any portion of the document. Non-conformant browsers such as Internet Explorer 4.x and Netscape 4.x were still widely used as late as 2000.
DOM Level 4 is currently being developed. Last Call Working Draft was released in February 2014.
By 2005, large parts of W3C DOM were well-supported by common ECMAScript-enabled browsers, including Microsoft Internet Explorer version 6 (from 2001), Opera, Safari and Gecko-based browsers (like Mozilla, Firefox, SeaMonkey and Camino).
When a web page is loaded, the browser creates a Document Object Model of the page.
Because DOM supports navigation in any direction (e.g., parent and previous sibling) and allows for arbitrary modifications, an implementation must at least buffer the document that has been read so far (or some parsed form of it).
Web browsers rely on layout engines to parse HTML into a DOM. Some layout engines, such as Trident/MSHTML, are associated primarily or exclusively with a particular browser, such as Internet Explorer. Others, such as Blink, WebKit, and Gecko, are shared by a number of browsers, such as Google Chrome, Opera, Safari, and Firefox. The different layout engines implement the DOM standards to varying degrees of compliance.
- Xerces is a collection of DOM implementations written in C++, Java and Perl
APIs that expose DOM implementations:
- JAXP (Java API for XML Processing) is an API for accessing DOM providers
- Lazarus (Free Pascal IDE) contains two variants of the DOM - with UTF-8 and ANSI format
- DOM Inspector is a web developer tool
- Ajax—a methodology employing DOM in combination with techniques for retrieving data without reloading a page.
- Application Object Model
- DOM scripting
- JDOM—a Java-based document object model for XML that integrates with DOM and SAX and uses parsers to build the document.
- SAX—serial access parser API for XML, an alternative to DOM.
- SXML—a model for representing XML and HTML in the form of S-expressions.
- TinyXml—efficient platform-independent XML library for C++.
- Koch, Peter-Paul (May 14, 2001). "The Document Object Model: an Introduction". Digital Web Magazine. Retrieved January 10, 2009.
- Le Hégaret, Philippe (2002). "The W3C Document Object Model (DOM)". World Wide Web Consortium. Retrieved January 10, 2009.
- Guisset, Fabian. "What does each DOM Level bring?". Mozilla Developer Center. Mozilla Project. Retrieved January 10, 2009.
- "Document Object Model (DOM)". http://www.w3.org/: W3C. Retrieved 2012-01-12.
The Document Object Model is a platform- and language-neutral interface that will allow programs and scripts to dynamically access and update the content, structure and style of documents.
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Document object models.
- Document Object Model by the World Wide Web Consortium
- Technology Reports
- What does your user agent claim to support?
- W3C DOM scripts and compatibility tables (Quirksmode)
- Gecko DOM Reference (Mozilla Developer Center)
- XJR with DOM, SAX2, and XPath interfaces
- Firefox plugin that lets you visualize a Web's page DOM in 3D