A query string is a part of a uniform resource locator (URL) that
assigns values to specified parameters. A query string commonly
includes fields added to a base URL by a Web browser or other client
application, for example as part of an HTML form.
A web server can handle a Hypertext Transfer Protocol (HTTP) request
either by reading a file from its file system based on the URL path or
by handling the request using logic that is specific to the type of
resource. In cases where special logic is invoked, the query string
will be available to that logic for use in its processing, along with
the path component of the URL.