JavaScript Basics

Overview

• JavaScript is one of the most widely used programming languages.
• Primarily used for:
  • Web development (front end)
  • Mobile development
  • Some back end development (e.g., Node.js)

Role in Web Development

• HTML & CSS define layout and style.
• JavaScript controls functionality and interactivity.
• Without JavaScript, web pages would be largely static.

Example Usage

Inline JavaScript

<script type="text/javascript">
  // JavaScript code here
</script>

• Within the page source code, JavaScript code is loaded with the <script>.

External JavaScript File

<script src="./script.js"></script>

• A web page can also load remote JavaScript code with src and the script's link.

Basic JavaScript Code Example

document.getElementById("button1").innerHTML = "Changed Text!";

• Changes the content of the element with id="button1".
• An example of basic use of JavaScript within a web page.

Tools for Practice

• JSFiddle for experimenting with JavaScript, HTML, and CSS.

Common Uses

• Real-time updates to page views and content.
• Accepting and processing user input.
• Performing HTTP requests via Ajax.
• Automation of complex processes.
• Driving advanced animations when combined with CSS.

Browser Support

• All modern browsers come with built-in JavaScript engines to execute code client-side.
• Enables fast, interactive experiences without round trips to the server.

JavaScript Frameworks

To enhance development efficiency, several frameworks and libraries are widely used:

• Angular
• React
• Vue
• jQuery

A listing and comparison of common JavaScript frameworks can be found here.

These frameworks:

• Provide tools and libraries to build feature-rich web applications.
• Allow dynamic generation of HTML.
• Can be used to simplify common functionalities like authentication.