orientType property
The orientType read-only property of the SVGMarkerElement
interface returns an SVGAnimatedEnumeration object indicating whether
the orient attribute is auto, an angle value, or something else.
This something else is most likely to be the keyword
auto-start-reverse however the spec leaves it open for this to be other
values. Unsupported values will generally be thrown away by the parser,
leaving the value the default of auto.
Implementation
external SVGAnimatedEnumeration get orientType;