class_06.md

JavaScript Objects

We have already learned that JavaScript variables are containers for data values.

Objects are variables too. But objects can contain many values.

JavaScript objects are containers for named values called properties or methods.

Object Properties

The name:values pairs in JavaScript objects are called properties:

Property	Property Value
firstName	John
lastName	Doe
age	50
eyeColor	blue

Document Object Model

With the object model, JavaScript gets all the power it needs to create dynamic HTML:

• JavaScript can change all the HTML elements in the page
• JavaScript can change all the HTML attributes in the page
• JavaScript can change all the CSS styles in the page
• JavaScript can remove existing HTML elements and attributes
• JavaScript can add new HTML elements and attributes
• JavaScript can react to all existing HTML events in the page
• JavaScript can create new HTML events in the page

When a web page is loaded, the browser creates a ** D **ocument ** O **bject ** M **odel of the page.

The ** HTML DOM ** model is constructed as a tree of Objects

What is the DOM?

The DOM is a W3C (World Wide Web Consortium) standard.

The DOM defines a standard for accessing documents:

*** "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." ***

** The W3C DOM standard is separated into 3 different parts: **

1. Core DOM - standard model for all document types
2. XML DOM - standard model for XML documents
3. HTML DOM - standard model for HTML documents

What is the HTML DOM?

The HTML DOM is a standard object model and programming interface for HTML. It defines:

• The HTML elements as objects
• The properties of all HTML elements
• The methods to access all HTML elements
• The events for all HTML elements

** In other words: The HTML DOM is a standard for how to get, change, add, or delete HTML elements. **