The spread (...) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created.

The less than (<) operator returns true if the left operand is less than the right operand, and false otherwise.

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

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

Quantifiers indicate numbers of characters or expressions to match.

The stroke-linecap attribute is a presentation attribute defining the shape to be used at the end of open subpaths when they are stroked.

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 startOffset attribute defines an offset from the start of the path for the initial current text position along the path after converting the path to the <textPath> element's coordinate system.

The delete operator removes a property from an object. If the property's value is an object and there are no more references to the object, the object held by that property is eventually released automatically.

The stop-opacity attribute defines the opacity of a given color gradient stop.