The unicode attribute specifies one or more Unicode characters indicating the sequence of Unicode characters which corresponds to a glyph.

The JavaScript exception "property is non-configurable and can't be deleted" occurs when it was attempted to delete a property, but that property is non-configurable.

The indexOf() method of Array instances returns the first index at which a given element can be found in the array, or -1 if it is not present.

The JavaScript exception "Invalid array length" occurs when specifying an array length that is either negative, a floating number or exceeds the maximum supported by the platform (i.e. when creating an Array or ArrayBuffer, or when setting the length property).

The JavaScript exception "TypeError: can't set prototype: it would cause a prototype chain cycle" occurs when an object's prototype is set to an object such that the prototype chain becomes circular (a and b both have each other in their prototype chains).

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

The width attribute defines the horizontal length of an element in the user coordinate system.

The word-spacing attribute specifies spacing behavior between words.

The Object.create() static method creates a new object, using an existing object as the prototype of the newly created object.

The y attribute defines a y-axis coordinate in the user coordinate system.