This function is convenient when encoding a string to be used in a query
part of a URL, as a convenient way to pass variables to the next page.
The string to be encoded.
Returns a string in which all non-alphanumeric characters except
-_. have been replaced with a percent
(%) sign followed by two hex digits and spaces encoded
as plus (+) signs. It is encoded the same way that the
posted data from a WWW form is encoded, that is the same way as in
application/x-www-form-urlencoded media type. This
differs from the » RFC 1738 encoding (see
rawurlencode()) in that for historical reasons, spaces
are encoded as plus (+) signs.