The stroke-opacity attribute is a presentation attribute defining the opacity of the paint server (color, gradient, pattern, etc.) applied to the stroke of a shape.

The stitchTiles attribute defines how the Perlin Noise tiles behave at the border.

The JavaScript exception "use of super property/member accesses only valid within methods or eval code within methods" occurs when the super.x or super[x] syntax is used outside of a method.

The JavaScript exception "functions cannot be labelled" occurs when a function declaration has a label before it.

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

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

The JavaScript exception "class constructors must be invoked with 'new'" occurs when a class constructor is called without the new keyword. All class constructors must be called with new.

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 u2 attribute specifies list of Unicode characters (refer to the description of the unicode attribute of the <glyph> element for a description of how to express individual Unicode characters) and/or ranges of Unicode characters, which identify a set of possible second glyph in a kerning pair.

The JavaScript exception "parameter after rest parameter" occurs when a rest parameter is followed by anything else in a parameter list, including another rest parameter, a formal parameter, or a trailing comma.