The overline-thickness attribute represents the ideal thickness of the overline. The overline thickness is expressed in the font's coordinate system.

A named backreference refers to the submatch of a previous named capturing group and matches the same text as that group. For unnamed capturing groups, you need to use the normal backreference syntax.

The keyTimes attribute represents a list of time values used to control the pacing of the animation.

The JavaScript strict mode-only exception "setting getter-only property" occurs when there is an attempt to set a new value to a property for which only a getter is specified.

The JavaScript Guide shows you how to use JavaScript and gives an overview of the language. If you need exhaustive information about a language feature, have a look at the JavaScript reference.

The JavaScript exception "missing variable name" is a common error. It is usually caused by omitting a variable name or a typographic error.

The orient attribute indicates how a marker is rotated when it is placed at its position on the shape.

The Promise.all() static method takes an iterable of promises as input and returns a single Promise. This returned promise fulfills when all of the input's promises fulfill (including when an empty iterable is passed), with an array of the fulfillment values. It rejects when any of the input's promises rejects, with this first rejection reason.

Character classes distinguish kinds of characters such as, for example, distinguishing between letters and digits.

Quantifiers indicate numbers of characters or expressions to match.