Question

What is the correct syntax for appending a query string parameter when I’m currently at the “root” of my site?

1) http://www.example.com/?foo=bar
2) http://www.example.com?foo=bar
3) http://www.example.com/&foo=bar

I’m certain #3 is completely wrong, but I’m unsure about 1 or 2. I’ve never come across this scenario, it’s always been appended to a filename with it’s extension — this odd use case came up on our team and I was left scratching my head.

Answer 1

Number one is the only correct one. See RFC1738 3.3:

   An HTTP URL takes the form:

      http://<host>:<port>/<path>?<searchpart>

   where <host> and <port> are as described in Section 3.1. If :<port>
   is omitted, the port defaults to 80.  No user name or password is
   allowed.  <path> is an HTTP selector, and <searchpart> is a query
   string. The <path> is optional, as is the <searchpart> and its
   preceding "?". If neither <path> nor <searchpart> is present, the "/"
   may also be omitted.