MDN’s new design is in Beta! A sneak peek: https://blog.mozilla.org/opendesign/mdns-new-design-beta/

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.

':' '/' '?' '#' '[' ']' '@' '!' '$' '&' "'" '(' ')' '*' '+' ',' ';' '=' '%' ' '
%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.

Learn more

General knowledge

Technical knowledge

  • RFC 3986, section 2.1, where this encoding is defined.

Document Tags and Contributors

 Contributors to this page: fscholz, teoli
 Last updated by: fscholz,