Dive into a treasure trove of notes, coding tutorials, past year questions, and a wealth of educational resources designed to enhance your learning and help you ace those exams—all conveniently gathered in one spot!

Full width home advertisement

Post Page Advertisement [Top]

JAVASCRIPT

JavaScript Logo

What is JavaScript

  • 1. JavaScript is a scripting language.
  • 2. It is used to create dynamic and interactive web pages.
  • 3. Runs in the browser (client-side) and also on servers using Node.js.
  • 4. Can manipulate HTML/CSS, handle events, and control browser behavior.
  • 5. Supports object-oriented and functional programming.
  • 6. Commonly used with HTML and CSS in web development.

Example:

<!Doctype html>
<html>
<body>
<p id="demo">Click the button!</p>
<button onclick="changeText()">Click Me</button>
<script>
function changeText() {
    document.getElementById("demo").innerHTML = "Hello, JavaScript!";
}
</script>
</body>
</html>

Types of JavaScript in terms of usage in HTML:

1. Inline JavaScript:

JavaScript code can be added directly within an HTML element using attributes like onclick and onmouseover.

Example:

<button onclick="alert('Hello!')">Click Me</button>

2. Internal JavaScript:

JavaScript is typically placed inside <script> tags within the same HTML file. You can easily use this tag in either the head or body sections.

Example:

<!Doctype html>
<html>
<head>
<title>Internal JS </title>
<script>
function greet(){
    alert("Welcome JavaScript");
}
</script>
</head>
<body>
<button onclick="greet()"> Click Me </button>
</body>
</html>

3. External JavaScript:

JavaScript is typically stored in a separate .js file, which you can link to using the <script src="script.js"> tag. You can place this tag either in the head or the body of your HTML document.

Example:

Script.js:

function showmessage(){
    alert("This is external JavaScript!");
}

Html File:

<!Doctype html>
<html>
<head>
<title>External JS </title>
<script src="script.js"></script>
</head>
<body>
<button onclick="showmessage()"> Click Me </button>
</body>
</html>

Comment and Types of comments in JavaScript:

  • JavaScript supports two types of comments.

1. Single-line Comment:

  • a. Starts with //
  • b. Anything after // on that line is ignored by the JavaScript engine.

Example:

// This is a single line comment

2. Multi-line Comment:

  • a. Starts with /* and ends with */
  • b. Can span across multiple lines.

Example:

/* This is a multi - line comment.
    It can describe logic or disable block of code.
*/
let age = 25;

No comments:

Post a Comment

Bottom Ad [Post Page]