The <filter> SVG element defines a custom filter effect by grouping atomic filter primitives. It is never rendered itself, but must be used by the filter attribute on SVG elements, or the filter CSS property for SVG/HTML elements.

There are several ways to color shapes (including specifying attributes on the object) using inline CSS, an embedded CSS section, or an external CSS file. Most SVG you'll find around the web use inline CSS, but there are advantages and disadvantages associated with each type.

JavaScript Date objects represent a single moment in time in a platform-independent format. Date objects encapsulate an integral number that represents milliseconds since the midnight at the beginning of January 1, 1970, UTC (the epoch).

The escape() function computes a new string in which certain characters have been replaced by hexadecimal escape sequences.

The <circle> SVG element is an SVG basic shape, used to draw circles based on a center point and a radius.

The bitwise AND (&) operator returns a number or BigInt whose binary representation has a 1 in each bit position for which the corresponding bits of both operands are 1.

The <ellipse> element is an SVG basic shape, used to create ellipses based on a center coordinate, and both their x and y radius.

The rest parameter syntax allows a function to accept an indefinite number of arguments as an array, providing a way to represent variadic functions in JavaScript.

A character class escape is an escape sequence that represents a set of characters.

The filter attribute specifies the filter effects defined by the <filter> element that shall be applied to its element.