Formular "action"

[Axel Richter]

Hallo,

Ist ein Leerstring eine gültige relative URL?

Nein.

Aber eine gültige URI
http://www.faqs.org/rfcs/rfc2396.html
...
URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]
alles optional

und
...
C.2.  Abnormal Examples

Although the following abnormal examples are unlikely to occur in
   normal practice, all URI parsers should be capable of resolving them
   consistently.  Each example uses the same base as above.

An empty reference refers to the start of the current document.

<>            =  (current document)
...

viele Grüße

Axel