On page 5 of this tutorial you can read this:
The method attribute of the <form> tag can be specified as "HEAD" to cause the
browser to send a HEAD request to the server.
According to W3C HTML40 Specs that is totally wrong:
<!ELEMENT FORM - - (%block;|SCRIPT)+ -(FORM) -- interactive form -->
<!ATTLIST FORM
%attrs; -- %coreattrs, %i18n, %events --
action %URI; #REQUIRED -- server-side form handler --
method (GET|POST) GET -- HTTP method used to submit the form--
enctype %ContentType; "application/x-www-form-urlencoded"
accept %ContentTypes; #IMPLIED -- list of MIME types for file upload --
name CDATA #IMPLIED -- name of form for scripting --
onsubmit %Script; #IMPLIED -- the form was submitted --
onreset %Script; #IMPLIED -- the form was reset --
accept-charset %Charsets; #IMPLIED -- list of supported charsets --
>