I\'m using the fragment identifier to create a permalink for AJAX events in my web app similar to this guy. Something like:
http://www.myapp.com/calendar#fi
One other RFC speak of that: RFC-1738
URL schemeparts for ip based protocols:
HTTP
httpurl = "http://" hostport [ "/" hpath [ "?" search ]]
hpath = hsegment *[ "/" hsegment ]
hsegment = *[ uchar | ";" | ":" | "@" | "&" | "=" ]
search = *[ uchar | ";" | ":" | "@" | "&" | "=" ]
See the RFC 3986.
fragment = *( pchar / "/" / "?" )
pchar = unreserved / pct-encoded / sub-delims / ":" / "@"
unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"
pct-encoded = "%" HEXDIG HEXDIG
sub-delims = "!" / "$" / "&" / "'" / "(" / ")"
/ "*" / "+" / "," / ";" / "="
So you can use !
, $
, &
, '
, (
, )
, *
, +
, ,
, ;
, =
, something matching %[0-9a-fA-F]{2}
, something matching [a-zA-Z0-9]
, -
, .
, _
, ~
, :
, @
, /
, and ?
http://tools.ietf.org/html/rfc3986#section-3.5:
fragment = *( pchar / "/" / "?" )
and
pchar = unreserved / pct-encoded / sub-delims / ":" / "@"
unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"
sub-delims = "!" / "$" / "&" / "'" / "(" / ")"
/ "*" / "+" / "," / ";" / "="
pct-encoded = "%" HEXDIG HEXDIG
So, combined, the fragment cannot contain #
, a raw %
, ^
, [
, ]
, {
, }
, \
, "
, <
and >
according to the RFC.