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 rx attribute defines a radius on the x-axis.

A regular expression (regex for short) allow developers to match strings against a pattern, extract submatch information, or simply test if the string conforms to that pattern. Regular expressions are used in many programming languages, and JavaScript's syntax is inspired by Perl.

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 v-alphabetic attribute defines indicates the alignment coordinate for glyphs to achieve alphabetic baseline alignment. The value is an offset in the font coordinate system relative to the glyph-specific vert-origin-x attribute.

The stroke-dashoffset attribute is a presentation attribute defining an offset on the rendering of the associated dash array.

The JavaScript exception "SyntaxError: private fields can't be deleted" occurs when delete is used on a private property of a class or an object.

The JavaScript exception "invalid Array.prototype.sort argument" occurs when the argument of Array.prototype.sort() isn't either undefined or a function which compares its operands.

The x attribute defines an x-axis coordinate in the user coordinate system.

The visibility attribute lets you control the visibility of graphical elements. With a value of hidden or collapse the current graphics element is invisible.