The constructor method is a special method of a class for creating and initializing an object instance of that class.

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 JavaScript strict mode-only exception "for-in loop head declarations may not have initializers" occurs when the head of a for...in contains an initializer expression, such as for (var i = 0 in obj). This is not allowed in for-in loops in strict mode. In addition, lexical declarations with initializers like for (const i = 0 in obj) are not allowed outside strict mode either.

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

The JavaScript exception "unlabeled break must be inside loop or switch" occurs when a break statement is not inside a loop or a switch statement.

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

The JavaScript exception "missing : after property id" occurs when objects are created using the object initializer syntax. A colon (:) separates keys and values for the object's properties. Somehow, this colon is missing or misplaced.

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