JavaScript is a prototype-based language — an object's behaviors are specified by its own properties and its prototype's properties. However, with the addition of classes, the creation of hierarchies of objects and the inheritance of properties and their values are much more in line with other object-oriented languages such as Java. In this section, we will demonstrate how objects can be created from classes.

The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.

The nullish coalescing assignment (??=) operator, also known as the logical nullish assignment operator, only evaluates the right operand and assigns to the left if the left operand is nullish (null or undefined).

The <line> SVG element is an SVG basic shape used to create a line connecting two points.

The addition (+) operator produces the sum of numeric operands or string concatenation.

The <feFuncB> SVG filter primitive defines the transfer function for the blue component of the input graphic of its parent <feComponentTransfer> element.

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

The <feSpecularLighting> SVG filter primitive lights a source graphic using the alpha channel as a bump map. The resulting image is an RGBA image based on the light color. The lighting calculation follows the standard specular component of the Phong lighting model. The resulting image depends on the light color, light position and surface geometry of the input bump map. The result of the lighting calculation is added. The filter primitive assumes that the viewer is at infinity in the z direction.

The decodeURI() function decodes a Uniform Resource Identifier (URI) previously created by encodeURI() or a similar routine.

The pointsAtZ attribute represents the z location in the coordinate system established by attribute primitiveUnits on the <filter> element of the point at which the light source is pointing, assuming that, in the initial local coordinate system, the positive z-axis comes out towards the person viewing the content and assuming that one unit along the z-axis equals one unit in x and y.