query string

A query string is the part of a uniform resource locator (URL) containing data that does not fit conveniently into a hierarchical path structure. The 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

Example

If a form is embedded in an HTML page as follows:

<form action="/hello" method="get">
  <input type="text" name="first" />
  <input type="text" name="second" />
  <input type="submit" />
</form>

and the user inserts the strings this is a field and was it clear (already)? in the two text fields and presses the submit button, the handler of the route /hello (the route specified by the action attribute of the form element in the above example) will receive the following query string:

first=this+is+a+field&second=was+it+clear+%28already%29%3F.

If the form is processed on the server by a CGI script, the script may typically receive the query string as an environment variable named QUERY_STRING.