JavaScript

on

                                                                        JavaScript

 JavaScript (JS) is a versatile and essential programming language commonly used for web development. It was originally created by Brendan Eich in 1995 and has since become an integral part of building dynamic and interactive web applications. JavaScript is often abbreviated as JS.

What Does JavaScript Work For?

JavaScript plays a crucial role in modern web development by providing the ability to add interactivity and manipulate web page content dynamically. Here are some key areas where JavaScript is used:

1- Enhancing User Experience: JavaScript allows developers to create interactive and engaging user interfaces. It can be used to validate forms, create animations, and build responsive designs.

2- Client-Side Scripting: JavaScript runs directly in the user's web browser, making it ideal for client-side scripting. This means that it can be used to modify web pages without requiring a server round-trip, improving the speed and responsiveness of web applications.

3- Web Applications: JavaScript is the foundation of many popular web frameworks and libraries like React, Angular, and Vue.js, which are used to build complex web applications.

4- Cross-Browser Compatibility: It helps ensure that web applications work consistently across various browsers and platforms, making it an essential tool for web developers.

5- API Integration: JavaScript can be used to interact with external APIs, enabling developers to fetch and display data from remote servers in real-time.

let's write a simple JavaScript code snippet to showcase how it can be used for basic web interactivity:

Code Explanation:

In this example, we have an HTML page with a heading, a paragraph, and a button. The JavaScript code embedded within the `<script>`tag does the following:

1- It retrieves a reference to the button element with the `getElementById` method.

2- It adds a click event listener to the button that responds to clicks by changing the text color of the `<body>`element to a randomly generated color.

This code demonstrates how JavaScript can be used to create a simple interactive feature on a web page. JavaScript's ability to manipulate the Document Object Model (DOM) makes it a powerful tool for building dynamic and user-friendly web applications.


                   What is JavaScript?
                                                                                                                                                                      Welcome to the MDN beginner's JavaScript course! In this article we will look at JavaScript from a high level, answering questions such as "What is it?" and "What can you do with it?", and making sure you are comfortable with JavaScript's purpose. 

Prerequisites: Basic computer literacy, a basic understanding of HTML and CSS.
Objective: To gain familiarity with what JavaScript is, what it can do, and how it fits into a website.

A high-level definition
JavaScript is a scripting or programming language that allows you to implement complex features on web pages — every time a web page does more than just sit there and display static information for you to look at — displaying timely content updates, interactive maps, animated 2D/3D graphics, scrolling video jukeboxes, etc. — you can bet that JavaScript is probably involved. It is the third layer of the layer cake of standard web technologies, two of which (HTML & CSS) we have covered in much more detail in other parts of the Learning Area.


  • HTML is the markup language that we use to structure and give meaning to our web content, for example defining paragraphs, headings, and data tables, or embedding images and videos in the page.
  • CSS is a language of style rules that we use to apply styling to our HTML content, for example setting background colors and fonts, and laying out our content in multiple columns.
  • JS is a scripting language that enables you to create dynamically updating content, control multimedia, animate images, and pretty much everything else. (Okay, not everything, but it is amazing what you can achieve with a few lines of JavaScript code.).
The three layers build on top of one another nicely. Let's take a button as an example. We can mark it up using HTML to give it structure and purpose:

HTML Code


Then we can add some CSS into the mix to get it looking nice:
CSS Code
& finally, we can add some JavaScript to implement dynamic behavior:
JS Code
Try clicking on this last version of the text label to see what happens (note also that you can find this demo on CodePen see the  run it live)!

JS can do a lot more than that — let's explore what in more detail.

So what can it really do?
The core client-side JS language consists of some common programming features that allow you to do things like:
  • Store useful values inside variables. In the above example for instance, we ask for a new name to be entered then store that name in a variable called  name.
  • Operations on pieces of text (known as "strings" in programming). In the above example we take the string "Player 1: " and join it to the name variable to create the complete text label, e.g. "Player 1: Chris".
  • Running code in response to certain events occurring on a web page. We used a  event in our example above to detect when the label is clicked and then run the code that updates the text label.
  • & much more!
What is even more exciting however is the functionality built on top of the client-side JavaScript language. So-called Application Programming Interfaces (APIs) provide you with extra superpowers to use in your JS code.

APIs are ready-made sets of code building blocks that allow a developer to implement programs that would otherwise be hard or impossible to implement. They do the same thing for programming that ready-made furniture kits do for home building — it is much easier to take ready-cut panels and screw them together to make a bookshelf than it is to work out the design yourself, go and find the correct wood, cut all the panels to the right size and shape, find the correct-sized screws, and then put them together to make a bookshelf.

They generally fall into two categories.
Browser APIs are built into your web browser, and are able to expose data from the surrounding computer environment, or do useful complex things.
  • The DOM (Document Object Model) API allows you to manipulate HTML and CSS, creating, removing and changing HTML, dynamically applying new styles to your page, etc. Every time you see a popup window appear on a page, or some new content displayed (as we saw above in our simple demo) for example, that's the DOM in action.
  • The Geolocation API retrieves geographical information. This is how Google Maps is able to find your location and plot it on a map.
  • The Canvas and WebGL APIs allow you to create animated 2D and 3D graphics. People are doing some amazing things using these web technologies
  • Audio and Video APIs like HTMLMediaElement and WebRTC allow you to do really interesting things with multimedia, such as play audio and video right in a web page, or grab video from your web camera and display it on someone else's computer (try our simple Snapshot demo to get the idea).
Third party APIs are not built into the browser by default, and you generally have to grab their code and information from somewhere on the Web.
There's a lot more available, too! However, don't get over excited just yet. You won't be able to build the next Facebook, Google Maps, or Instagram after studying JS for 24 hours — there are a lot of basics to cover first. And that's why you're here — let's move on!










Comments

Post a Comment