The let declaration declares re-assignable, block-scoped local variables, optionally initializing each to a value.

The instanceof operator tests to see if the prototype property of a constructor appears anywhere in the prototype chain of an object. The return value is a boolean value. Its behavior can be customized with Symbol.hasInstance.

Apart from graphic primitives like rectangles and circles, SVG offers a set of elements to embed other types of content in images as well.

The RegExp object is used for matching text with a pattern.

The switch statement evaluates an expression, matching the expression's value against a series of case clauses, and executes statements after the first case clause with a matching value, until a break statement is encountered. The default clause of a switch statement will be jumped to if no case matches the expression's value.

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

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 <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.

Operator precedence determines how operators are parsed concerning each other. Operators with higher precedence become the operands of operators with lower precedence.