PHP and the Document Object Model 
Obtained from the book, XML and PHP by Vikram Vaswani
PHP and the Document Object Model (DOM)
Document Object Model (DOM)
The Document Object Model (DOM) is a standard interface to access and manipulate structured data. As the name suggests, it does this by modeling, or representing, a document as a hierarchical tree of objects. A number of different object types are defined in the W3C's DOM specification; these objects expose methods and attributes that can be used by the application layer to navigate and process the DOM tree, exploit the relationships between the different branches of the tree, and extract information from it. The W3C's DOM specification defines a number of different objects to represent the different structures that appear within an XML document. For example, elements are represented by an Element object, whereas attributes are represented by Attr objects. Each of these different object types exposes specific methods and properties. Element objects expose a tagName property containing the element name and getAttribute() and setAttribute() methods for attribute manipulation, whereas Attr objects expose a value property containing the value of the particular attribute. These methods and properties can be used by the application layer to navigate and process the DOM tree, exploit the relationships between the different branches of the tree, and extract information from it. The very first specification of the DOM (DOM Level 1) appeared on the W3C's web site in October 1998, and simply specified the "core" features of the DOM—the basic objects and the interfaces to them. The next major upgrade, DOM Level 2, appeared in November 2000; it examined the DOM from the perspective of core functions, event handling, and document traversal. DOM Level 3, which is currently under development, builds on past work, and incorporates additions and changes from other related technologies (XPath, abstract schemas, and so on). As a standard interface to
PHP and the Document Object Model (DOM)
Document Object Model (DOM)
The Document Object Model (DOM) is a standard interface to access and manipulate structured data. As the name suggests, it does this by modeling, or representing, a document as a hierarchical tree of objects. A number of different object types are defined in the W3C's DOM specification; these objects expose methods and attributes that can be used by the application layer to navigate and process the DOM tree, exploit the relationships between the different branches of the tree, and extract information from it. The W3C's DOM specification defines a number of different objects to represent the different structures that appear within an XML document. For example, elements are represented by an Element object, whereas attributes are represented by Attr objects. Each of these different object types exposes specific methods and properties. Element objects expose a tagName property containing the element name and getAttribute() and setAttribute() methods for attribute manipulation, whereas Attr objects expose a value property containing the value of the particular attribute. These methods and properties can be used by the application layer to navigate and process the DOM tree, exploit the relationships between the different branches of the tree, and extract information from it. The very first specification of the DOM (DOM Level 1) appeared on the W3C's web site in October 1998, and simply specified the "core" features of the DOM—the basic objects and the interfaces to them. The next major upgrade, DOM Level 2, appeared in November 2000; it examined the DOM from the perspective of core functions, event handling, and document traversal. DOM Level 3, which is currently under development, builds on past work, and incorporates additions and changes from other related technologies (XPath, abstract schemas, and so on). As a standard interface to