The mathematical attribute indicates the alignment coordinate for glyphs to achieve mathematical baseline alignment for horizontally oriented glyph layouts. The value is an offset in the font coordinate system.

The media attribute specifies a media query that must be matched for a style sheet to apply.

The extends keyword is used in class declarations or class expressions to create a class that is a child of another class.

The k1 attribute defines one of the values to be used within the arithmetic operation of the <feComposite> filter primitive.

The JavaScript exception "x is (not) y" occurs when there was an unexpected type. Oftentimes, unexpected undefined or null values.

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 path attribute has two different meanings, either it defines a text path along which the characters of a text are rendered, or a motion path along which a referenced element is animated.

The constructor method is a special method of a class for creating and initializing an object instance of that class.

The JavaScript exception ""use strict" not allowed in function" occurs when a "use strict" directive is used at the top of a function with default parameters, rest parameters, or destructuring parameters.

The JavaScript exception "missing : after property id" occurs when objects are created using the object initializer syntax. A colon (:) separates keys and values for the object's properties. Somehow, this colon is missing or misplaced.