Percent-encoding
Percent-encoding is a mechanism to encode 8-bit characters that have specific meaning in the context of URLs. It is sometimes called URL encoding. The encoding consists of substitution: A '%' followed by the hexadecimal representation of the ASCII value of the replace character.
Special characters needing encoding are: ':'
, '/'
, '?'
, '#'
, '['
, ']'
, '@'
, '!'
, '$'
, '&'
, "'"
, '('
, ')'
, '*'
, '+'
, ','
, ';'
, '='
, as well as '%'
itself. Other characters don't need to be encoded, though they could.
Character | Encoding |
---|---|
':' |
%3A |
'/' |
%2F |
'?' |
%3F |
'#' |
%23 |
'[' |
%5B |
']' |
%5D |
'@' |
%40 |
'!' |
%21 |
'$' |
%24 |
'&' |
%26 |
"'" |
%27 |
'(' |
%28 |
')' |
%29 |
'*' |
%2A |
'+' |
%2B |
',' |
%2C |
';' |
%3B |
'=' |
%3D |
'%' |
%25 |
' ' |
%20 or + |
Depending on the context, the character ' '
is translated to a '+'
(like in the percent-encoding version used in an application/x-www-form-urlencoded
message), or in '%20'
like on URLs.
See also
- Definition of percent-encoding in Wikipedia.
- RFC 3986, section 2.1, where this encoding is defined.