For accessing and manipulating documents, a standard is defined by the DOM.
“The W3C Document Object Model (DOM) is a platform and language-neutral interface that allows programs and scripts to dynamically access and update the content, structure, and style of a document.”
For accessing and manipulating HTML documents, the HTML DOM defines a standard way and presents an HTML document as a tree-structure. For accessing and manipulating XML documents, the XML DOM defines a standard way and presents an XML document as a tree-structure. For working with HTML or XML, a good understanding of DOM is necessary.
HTML DOM:
Through the HTML DOM, we can access all the HTML elements.
Example:
Hello World!
Output 1:
Output 2:
Explanation:
In the above example, the value of an HTML element changes with id=”demo”.
XML DOM:
How to get, change, add, and delete XML elements is defined by the XML DOM as a standard. Through the XML DOM, we can access all the XML elements.
Books.xml:
ABC Author Name 2020 100.00 XQuery Book Author 1 Author 2 Author 3 Author 4 2004 350.00
Example:
Output:
Explanation:
In the above example, we are loading a text string into an XML DOM object. We then extract the info from it with JavaScript. The below line of code retrieves the text value of the first <title> element in an XML document:
txt = xmlDoc.getElementsByTagName("title")[0].childNodes[0].nodeValue;