Classes are a template for creating objects. They encapsulate data with code to work on that data. Classes in JS are built on prototypes but also have some syntax and semantics that are unique to classes.

Whereas HTML defines a webpage's structure and content and CSS sets the formatting and appearance, JavaScript adds interactivity to a webpage and creates rich web applications.

The if...else statement executes a statement if a specified condition is truthy. If the condition is falsy, another statement in the optional else clause will be executed.

The encodeURIComponent() function encodes a URI by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF-8 encoding of the character (will only be four escape sequences for characters composed of two surrogate characters). Compared to encodeURI(), this function encodes more characters, including those that are part of the URI syntax.

The do...while statement creates a loop that executes a specified statement as long as the test condition evaluates to true. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.

Boolean values can be one of two values: true or false, representing the truth value of a logical proposition.

The intercept attribute defines the intercept of the linear function of color component transfers when the type attribute is set to linear.

The fy attribute defines the y-axis coordinate of the focal point for a radial gradient.

The class declaration creates a binding of a new class to a given name.

The preserveAspectRatio attribute indicates how an element with a viewBox providing a given aspect ratio must fit into a viewport with a different aspect ratio.