Modifying the HTML Page using JavaScript

JavaScript allows you to dynamically change the content, attributes, and style of HTML elements on your webpage. Here's a step-by-step tutorial. 

1. Changing Text Content:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Modify HTML with JavaScript</title>
</head>
<body>
    <h1 id="myHeading">Hello, World!</h1>

    <script>
        // Accessing an element by its ID
        var headingElement = document.getElementById('myHeading');

        // Modifying the text content of the element
        headingElement.textContent = 'Greetings, JavaScript!';
    </script>
</body>
</html>

2. Changing HTML Structure:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Modify HTML Structure</title>
</head>
<body>
    <div id="myDiv">This is a div.</div>

    <script>
        // Accessing an element by its ID
        var divElement = document.getElementById('myDiv');

        // Creating a new paragraph element
        var newParagraph = document.createElement('p');
        newParagraph.textContent = 'This is a new paragraph.';

        // Appending the new paragraph to the existing div
        divElement.appendChild(newParagraph);
    </script>
</body>
</html>

3. Changing Attributes:


<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Modify HTML Attributes</title>
</head>
<body>
    <img id="myImage" src="original.jpg" alt="Original Image">

    <script>
        // Accessing an element by its ID
        var imageElement = document.getElementById('myImage');

        // Modifying the 'src' attribute of the image
        imageElement.src = 'new-image.jpg';

        // Modifying the 'alt' attribute of the image
        imageElement.alt = 'New Image';
    </script>
</body>
</html>

These examples demonstrate the basics of modifying the HTML page using JavaScript. As you become more familiar with these concepts, you can create dynamic and interactive web pages by manipulating the DOM with JavaScript.