Functions in JavaScript are used to define reusable blocks of code that can be called multiple times.

• Functions can be used to perform specific tasks or calculations.

• Functions can be passed as arguments to other functions.

• Functions can be assigned to variables or properties of objects.

• Functions can be used to create closures for encapsulating data.

• Functions can be used to create custom methods for objects.

getElementById is used in JavaScript to access and manipulate an element in the DOM by its unique ID.

• Used to retrieve a specific element from the DOM by its ID

• Allows for manipulation of the element's properties, styles, and content

• Commonly used in event handling and dynamic content updates

There are three types of CSS: inline, internal, and external.

• Inline CSS is applied directly to an HTML element using the style attribute.

• Internal CSS is defined within the head section of an HTML document using the style tag.

• External CSS is stored in a separate file and linked to the HTML document using the link tag.