WEB222 - Week 7

From HTML to the DOM

• HTML provides initial structure for web pages.
• Browsers parse HTML into a modifiable DOM Tree.
• DOM Tree: A living version of HTML consisting of nodes.
  • Types of Nodes: Elements, Text Nodes, Attribute Nodes.
• DOM Tree structure is crucial for web page rendering.
• Developer tools in browsers allow interaction with the DOM.

Programming the DOM

• DOM: Document Object Model, an interface for scripts to modify documents.
• JavaScript utilizes DOM to make web pages dynamic.

DOM Access in JavaScript

• Accessed via window.document. let document = window.document;
• Methods to find elements:
  • document.getElementById(id)
  • document.querySelector(selectors)
  • document.querySelectorAll(selectors)

Modifying the DOM

• Create elements:
  • document.createElement(name)
  • document.createTextNode(text)
• Insert elements:
  • .appendChild()
  • .insertBefore(new, old)
• Remove elements:
  • .removeChild()

Inspecting and Modifying Elements

• Element Properties:
  • element.id, element.innerHTML, element.parentNode
• Element Methods:
  • .querySelector(), .querySelectorAll(), .scrollIntoView()

Events in the DOM

• Event-Driven Programming: Functions execute in response to events.
• Registering Event Handlers:
  • element.onevent = function(e) {...}
  • element.addEventListener('event', function(e) {...})
• Common Events: load, click, keypress, change.

The Event Object

• Contains info about the event.
• Useful methods:
  • e.preventDefault(), e.stopPropagation()

Timers

• Delays using:
  • setTimeout(function, delayMS)
  • setInterval(function, delayMS)

DOM Programming Exercise

• Create and modify HTML pages using JavaScript:
  • Load images and text dynamically.
  • Handle user interactions and events.
  • Use timers and event handlers to create interactive web experiences.