The data-* SVG attributes are called custom data attributes. They let SVG markup and its resulting DOM share information that standard attributes can't, usually for scripting purposes. Their custom data are available via the SVGElement interface of the element the attributes belong to, with the SVGElement.dataset property.

The SVG <tspan> element defines a subtext within a <text> element or another <tspan> element. It allows for adjustment of the style and/or position of that subtext as needed.

SVG Attribute reference home

The super keyword is used to access properties on an object literal or class's [[Prototype]], or invoke a superclass's constructor.

The for statement creates a loop that consists of three optional expressions, enclosed in parentheses and separated by semicolons, followed by a statement (usually a block statement) to be executed in the loop.

The flood-opacity attribute indicates the opacity value to use across the current filter primitive subregion.

The baseProfile attribute describes the minimum SVG language profile that the author believes is necessary to correctly render the content. The attribute does not specify any processing restrictions; It can be considered metadata.

The JavaScript strict mode-only exception "'arguments' can't be defined or assigned to in strict mode code" or "'eval' can't be defined or assigned to in strict mode code" occurs when attempting to create a binding called arguments or eval, or assign to such a name.

Scalable Vector Graphics (SVG) is an XML-based markup language for describing two-dimensional based vector graphics.

JavaScript is designed on a simple object-based paradigm. An object is a collection of properties, and a property is an association between a name (or key) and a value. A property's value can be a function, in which case the property is known as a method.