Problem Domain, Objects, and the DOM

Problem Domain

• Understanding the problem domain is the hardest part of programming

• Problem domains are hard because it is very difficult to solve a problem before you know the question

• 2 things you can do:

  • Make the problem domain easier

  • Get better at understanding the problem domain

JavaScript - Jon Duckett

• Chapter 3: Object Literals

  • Objects group together a set of variables and functions to create a model

  • In an object: variables become known as properties

  • In an object: functions become known as methods

  • Example below: This object represents a hotel

    • var Hotel = { name: ‘Quay’. rooms: 40, booked: 25, gym: true, roomTypes: [‘twin’, ‘double’, ‘suite’], checkAvailability: function() { return this.rooms - this.booked; } }

    • Name, rooms, booked, gym, roomTypes are PROPERTIES

    • checkAvailability is the METHOD

• Chapter 5: Document Object Model

  • DOM specifies how browsers should create a model of an HTML page and how JavaScript can access and update the contents of a web page while it is in the browser window

  • DOM is neither part of HTML nor part of JavaScript; it is a separate set of rules.

  • It is implemated by all browser makers and covers two areas:

    • Making a model of the HTML page

    • Accessing and changing the HTML page

    • DOM trees have four types of nodes: document nodes, element nodes, attribute nodes, and text nodes

    • You can select element nodes by their id or class attributes, by tag name, or using CSS selector syntax

    • Browsers off tools for viewing the DOM tree

Information taken from “Javascript & JQuery Interactive Front-End Web Development” by Jon Duckett and the web article Understanding the problem domain is the hardest part of programming