Characters allowed in GET parameter

Question

Which characters are allowed in GET parameters without encoding or escaping them? I mean something like this:

http://www.example.org/page.php?name=XYZ

What can you have there instead of XYZ? I think only the following characters:

• a-z (A-Z)
• 0-9
• -
• _

Is this the full list or are there additional characters allowed?

I hope you can help me. Thanks in advance!

Answer 1

"." | "!" | "~" | "*" | "'" | "(" | ")" are also acceptable [RFC2396]. Really, anything can be in a GET parameter if it is properly encoded.