Is it a bad practice to use a GET parameter (in URL) with no value?

Question

I\'m in a little argument with my boss about URLs using GET parameters without value. E.g.

http://www.example.com/?logout

I see this kind of lin

Answer 1

RFC 2396, "Uniform Resource Identifiers (URI): Generic Syntax", §3.4, "Query Component" is the authoritative source of information on the query string, and states:

The query component is a string of information to be interpreted by the resource.

[...]

Within a query component, the characters ";", "/", "?", ":", "@", "&", "=", "+", ",", and "$" are reserved.

RFC 2616, "Hypertext Transfer Protocol -- HTTP/1.1", §3.2.2, "http URL", does not redefine this.

In short, the query string you give ("logout") is perfectly valid.