Science Knowings: HTML Course For Social Media

HTML DOM

HTML DOM

Welcome to the topic of HTML DOM (Document Object Model). In the previous session, we learned about HTML document structure. Today, we'll dive into the DOM, an essential aspect of manipulating and interacting with HTML documents.

What is the Document Object Model (DOM)?

The DOM is a programming interface that represents an HTML document as a tree structure. It allows us to access and modify every element, attribute, and node in the document through code.

Advantages of Using the DOM

Using the DOM provides several advantages:

  • Dynamic content: Update and manipulate the page's content without reloading it.
  • Improved interactivity: Create interactive elements like menus, forms, and animations.
  • Easier debugging: Inspect and modify the DOM to troubleshoot issues.

Accessing and Modifying the DOM

To access and modify the DOM, we use JavaScript methods:

  • getElementById(): Access an element by its unique ID.
  • getElementsByClassName(): Access all elements with the specified class name.
  • getElementsByTagName(): Access all elements with the specified tag name.
  • querySelector(): Access an element using a CSS selector.
  • querySelectorAll(): Access all elements matching a CSS selector.

The Element Object

The Element object represents an HTML element. It provides properties and methods to access and modify the element's attributes, content, and style.

The NodeList Object

The NodeList object represents a collection of HTML elements that share a common ancestor. It provides methods to iterate through and access individual elements in the collection.

DOM Manipulation Methods

In addition to accessing elements, we can also modify the DOM using JavaScript methods:

  • createElement(): Create a new HTML element.
  • appendChild(): Add a new child element to an existing element.
  • removeChild(): Remove a child element from an existing element.
  • insertBefore(): Insert a new element before an existing element.
  • replaceChild(): Replace an existing element with a new element.

getElementById()

The getElementById() method accesses an element by its unique ID. It returns the first element that matches the specified ID.

var element = document.getElementById('uniqueId');

getElementsByClassName()

The getElementsByClassName() method accesses all elements with the specified class name. It returns a NodeList containing the matching elements.

var elements = document.getElementsByClassName('className');

getElementsByTagName()

The getElementsByTagName() method accesses all elements with the specified tag name. It returns a NodeList containing the matching elements.

var elements = document.getElementsByTagName('tagName');

querySelector()

The querySelector() method accesses an element using a CSS selector. It returns the first element that matches the selector.

var element = document.querySelector('css-selector');

querySelectorAll()

The querySelectorAll() method accesses all elements matching a CSS selector. It returns a NodeList containing the matching elements.

var elements = document.querySelectorAll('css-selector');

createElement()

The createElement() method creates a new HTML element with the specified tag name. It returns the newly created element.

var element = document.createElement('tagName');

appendChild()

The appendChild() method adds a new child element to an existing element. It appends the child to the end of the existing element's child list.

parent.appendChild(child);

removeChild()

The removeChild() method removes a child element from an existing element. It removes the specified child from the existing element's child list.

parent.removeChild(child);

insertBefore()

The insertBefore() method inserts a new element before an existing element. It inserts the new element as a sibling of the existing element, before the specified sibling.

parent.insertBefore(newElement, existingElement);

replaceChild()

The replaceChild() method replaces an existing element with a new element. It removes the existing element from the parent element's child list and inserts the new element in its place.

parent.replaceChild(newElement, existingElement);

Next Topic: HTML Events

In the next session, we'll explore HTML events, which allow us to respond to user interactions like clicks, mouse movements, and form submissions. Follow us to learn more!