2009 Mar 23, 11:06The HTML5 spec tells us how it is in the real world for URLs: "This specification defines various algorithms for dealing with Web addresses intended for use by HTML user agents. For historical
reaons, in order to be compatible with existing Web content HTML user agents need to implement a number of processes not defined by the URI and IRI specifications [RFC3986], [RFC3987]."
html html5 url uri reference w3c