URL fragment (#) allowed characters
Solution 1:
tl;dr
The fragment identifier component can contain:
-
0-9 -
a-z -
A-Z -
?/:@-._~!$&'()*+,;= - percent-encoded characters (a
%followed by two hexadecimal digits)
How can I find this out?
The URI standard is STD 66, which currently maps to RFC 3986.
In this document, you’ll find everything you need to know.
The fragment identifier component is defined in section 3.5:
fragment = *( pchar / "/" / "?" )
This means that the fragment can contain nothing or (any combination of)
- characters defined in pchar
- the
/ - the
?
Definition of pchar
Refer to the appendix A. to see how pchar is defined:
pchar = unreserved / pct-encoded / sub-delims / ":" / "@"
So this adds
- characters defined in unreserved
- characters defined in pct-encoded
- characters defined in sub-delims
- the
: - the
@
Definition of unreserved
Now check how unreserved is defined:
unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"
This adds
- characters defined in ALPHA
- characters defined in DIGIT
- the
- - the
. - the
_ - the
~
Definition of ALPHA and DIGIT
Check how ALPHA and DIGIT are defined. They are not listed in the appendix, because they are from the core ABNF rules, as is explained in section 1.3:
ALPHA (letters), […] DIGIT (decimal digits) […]
So this adds
-
a-z,A-Z -
0-9
Definition of pct-encoded
Check how pct-encoded is defined:
pct-encoded = "%" HEXDIG HEXDIG
This allows for any percent-encoded character.
Definition of sub-delims
Check how sub-delims is defined:
sub-delims = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="
This adds
- the
! - the
$ - the
& - the
' - the
( - the
) - the
* - the
+ - the
, - the
; - the
=
Solution 2:
It's a bit tricky to find the valid characters, but the file commented above does contain the information if you read deep enough.
The available characters are as follow:
- "!"
- "$"
- "&"
- "'"
- "("
- ")"
- "*"
- "+"
- ","
- ";"
- "="
- "?"
- "@"
- ALPHA
- DIGIT
- "-"
- "."
- "_"
- "~"
- "%" HEXDIG HEXDIG
- ":"
- "/"