The strict equality (===) operator checks whether its two operands are equal, returning a Boolean result. Unlike the equality operator, the strict equality operator always considers operands of different types to be different.

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

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

The bitwise OR assignment (|=) operator performs bitwise OR on the two operands and assigns the result to the left operand.

A character class matches any character in or not in a custom set of characters. When the v flag is enabled, it can also be used to match finite-length strings.

The JavaScript exception "invalid 'instanceof' operand" occurs when the right-hand side operands of the instanceof operator isn't used with a constructor object, i.e. an object which has a prototype property and is callable.

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

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 pathLength attribute lets authors specify a total length for the path, in user units. This value is then used to calibrate the browser's distance calculations with those of the author, by scaling all distance computations using the ratio pathLength / (computed value of path length).

The URIError object represents an error when a global URI handling function was used in a wrong way.