<https://www.aspsnippets.com/Articles/Enumeration-in-JavaScript-How-to-define-and-use-Enum-in-JavaScript.aspx>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.aspsnippets.com/Articles/Enumeration-in-JavaScript-How-to-define-and-use-Enum-in-JavaScript.aspx>