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 document, choosing the appearance of a page, or jumping to positions in multimedia content.
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.
A typical URL containing a query string is as follows:
When a server receives a request for such a page, it may run a program, passing the query string, which in this case is name=ferret, unchanged to the program. The question mark is used as a separator, and is not part of the query string.[1] [2]
Web frameworks may provide methods for parsing multiple parameters in the query string, separated by some delimiter. In the example URL below, multiple query parameters are separated by the ampersand, "&":