DOM NodeList in XML

A NodeList is a collection (like an array) of nodes returned by DOM methods such as:

• getElementsByTagName()

• childNodes

• querySelectorAll() (in HTML DOM)

What is a NodeList?

• It is array-like, meaning you can access items by index: nodeList[0].

• It is live or static depending on the method (e.g., getElementsByTagName returns a live NodeList, reflecting changes in the DOM).

• You can loop over a NodeList using for loop or for...of (in modern browsers).

Example XML

<library>  <book id="101"><title>Effective Java</title></book>  <book id="102"><title>Clean Code</title></book>  <book id="103"><title>JavaScript: The Good Parts</title></book></library>

Getting a NodeList in JavaScript

// Assuming xmlDoc is the parsed XML documentconst books = xmlDoc.getElementsByTagName("book"); // NodeList of all <book> elementsconsole.log(books.length);  // Number of <book> nodes// Access individual nodesconst firstBook = books[0];console.log(firstBook.getAttribute("id"));  // "101"

Looping Through a NodeList

for (let i = 0; i < books.length; i++) {  const book = books[i];  const title = book.getElementsByTagName("title")[0].textContent;  console.log(`Book ID: ${book.getAttribute("id")}, Title: ${title}`);}

Or using modern syntax:

for (const book of books) {  const title = book.getElementsByTagName("title")[0].textContent;  console.log(`Book ID: ${book.getAttribute("id")}, Title: ${title}`);}

Important Notes

• NodeList is not exactly an Array, so array methods like .map(), .filter() won’t work unless you convert it:

const booksArray = Array.from(books);booksArray.forEach(book => {  console.log(book.getAttribute("id"));});

• In older browsers, you may need for loops instead of for...of.

Summary

If you want, I can provide a runnable HTML + JS example demonstrating NodeList usage on XML!