Javascript Object Creation
JavaScript object creation involves defining and instantiating objects, which are instances of classes or prototypes. Objects can be created using object literals, constructor functions, or the `class` keyword in modern JavaScript. This process allows for the encapsulation of data and behavior, enabling the creation of complex and reusable code structures.
3 Key excerpts on "Javascript Object Creation"
eBook - ePub- David Karlins, Doug Sahlin(Authors)
- 2012(Publication Date)
- For Dummies(Publisher)
...These are somewhat flexible and relative terms. JavaScript defines its parts in much more loose and more flexible ways than many other languages. In JavaScript, most things can be considered objects. If you define a new variable (var x;), you’re creating a new object. Shortly, we explore functions in JavaScript, which do things like calculate and place the current date in a document. These functions could also be considered an object as well. The final concept we’ll throw into the hopper is event handlers, which are triggered by actions in a browser. Here are a few examples of event handlers: ♦ onload triggers a JavaScript when a web page opens. ♦ onunload triggers a JavaScript when a web page closes. ♦ onclick triggers a JavaScript when a user clicks an element. We use these event handlers in the examples we are about to explore. Using JavaScript Date Functions Take a minute to quickly revisit the document.write example from earlier in this chapter: <script type=”text/javascript”> document.write(“This is JavaScript”); </script> That code simply prints This is JavaScript on a page...
- Kenneth J. Luterbach(Author)
- 2018(Publication Date)
- Routledge(Publisher)
...Extending knowledge across multiple development environments increases your capabilities and favors efforts to make instructional apps ubiquitous across multiple digital devices. 3.1 Procedural Programming JavaScript is both a procedural programming language and object oriented. We begin with procedural programming features and then proceed to objective-oriented techniques, which arise in the section on Software Development Kits (Section 3.2.2). Using a procedural programming language, you can solve problems and express yourself creatively. 3.1.1 Input and Output To convey the effects of data processing to users, computer programs output results, which may be numeric or alphabetic. A series of alphabetic characters, such as “Hello, World,” is called a string. Our first JavaScript program will display “Hello, World!” and will run in either the Google Chrome or Firefox web browser. 1 To begin, open the JavaScript Console in Google Chrome by pressing Option-Command-J on a Mac or Control-Shift-I on a Windows PC (or you could drop down the View menu and select Developer; JavaScript Console). Alternatively, open the JavaScript Console in Firefox by pressing Option-Command-K on a Mac or Control-Shift-K on a Windows PC (or you could drop down the Tools menu and select Web Developer; Web Console). On a Windows PC, whether using Google Chrome or Firefox, make sure the Console tab is selected. Whether using a Mac or a Windows PC, in the JavaScript Console, type the following line of JavaScript code and press the Enter or Return key. console.log("Hello, World"); Do not be concerned that the word, undefined appears below “Hello, World.” Also in the JavaScript Console, enter a few arithmetic expressions, such as the following, and press the Enter or Return key after each expression. 3 + 8 28 * 2 + 1 (4 − 20) / 8 6 It is helpful to know that one can run JavaScript code within popular web browsers, but we will use SpiderMonkey JavaScript because it has several advantages...
eBook - ePubConfident Web Design
Master the Fundamentals of Website Creation and Supercharge Your Career
- Kenny Wood(Author)
- 2018(Publication Date)
- Kogan Page(Publisher)
...Pretty much everything in JavaScript is an object. Strings can be objects, numbers can be objects, functions are objects, values are objects, dates are objects, objects are objects. So by now you’ve probably got the message. Objects are everywhere in JavaScript. So, the obvious question is, what’s an object? Well, in programming, objects can be compared directly with an object in real life. Let’s take the example of an animal. An animal has properties, right? Like its name, its colour, its size, its weight, its breed or its age. An animal also has methods: an animal can talk, it can sit, it can roll over, it can eat and sleep. Well, you can define an object in JavaScript that represents this exact same idea. Objects simply contain data about a ‘thing’. Objects are simply variables that contain more than one piece of information. Ever used a website that you have your own profile on? Which contains your email address, password, address, etc? Well, it’s extremely likely that that information will be joined together into an object in the website’s JavaScript code. Objects should contain all of the relevant information about one thing. Now, enough explaining. Let’s see some code and step through it: var animal = { name: “Buster”, age: 6, type: “Husky”, colour: “blue”, speak: function() { console.log(”Woof”); } } Now this might look a bit complex at first, but it’s actually extremely simple. Ignore the exact syntax for now and just glance over what is actually happening. We are simply assigning information to keywords. We are just entering data that we want to assign to a term. We are saying that we want the animal’s name to be Buster, and his type should be husky, etc. Then we are giving him a function to speak, which we are calling ‘speak’...
