Editing Query string (section)

=== Web forms ===
One of the original uses was to contain the content of an [[form (HTML)|HTML form]], also known as web form. In particular, when a form containing the fields <code>field1</code>, <code>field2</code>, <code>field3</code> is submitted, the content of the fields is encoded as a query string as follows:
{{quote|1=<code>field1=value1&amp;field2=value2&amp;field3=value3...</code>}}
* The query string is composed of a series of field-value pairs.
* Within each pair, the field name and value are separated by an [[equals sign]], "<code>=</code>".
* The series of pairs is separated by the [[ampersand]], "<code>&amp;</code>" ([[semicolons]] "<code>;</code>" are not recommended by the [[W3C]] anymore, see below).

While there is no definitive standard, most [[web framework]]s allow multiple values to be associated with a single field (e.g. <code>field1=value1&field1=value2&field2=value3</code>).<ref>{{cite web|url=https://docs.oracle.com/javaee/6/api/javax/servlet/ServletRequest.html#getParameterValues(java.lang.String) |title=ServletRequest (Java EE 6 )|website=docs.oracle.com |date=2011-02-10|access-date=2013-09-08}}</ref><ref>{{cite web|url=https://stackoverflow.com/questions/1746507/authoritative-position-of-duplicate-http-get-query-keys |title=uri – Authoritative position of duplicate HTTP GET query keys|website=Stack Overflow |date=2013-06-09|access-date=2013-09-08}}</ref>

For each [[Field (computer science)|field]] of the form, the query string contains a pair <code><var>field</var>=<var>value</var></code>. Web forms may include fields that are not visible to the user; these fields are included in the query string when the form is submitted.

This convention is a [[W3C]] recommendation.<ref name="w3c-recom">[https://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type Forms in HTML documents]. W3.org. Retrieved on 2013-09-08.</ref> In the recommendations of 1999, W3C recommended that all web servers support [[semicolon]] separators in addition to [[ampersand]] separators<ref>[http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.2.2 Performance, Implementation, and Design Notes]. W3.org. Retrieved on 2013-09-08.</ref> to allow [[application/x-www-form-urlencoded]] query strings in URLs within HTML documents without having to entity escape ampersands. Since 2014, W3C recommends to use only [[ampersand]] as query separator.<ref name="w3c-recom-2014">{{cite web | url=https://www.w3.org/TR/2014/REC-html5-20141028/forms.html#url-encoded-form-data | title=4.10 Forms — HTML5 }}</ref>

The form content is only encoded in the URL's query string when the form submission method is [[GET (HTTP)|GET]]. The same encoding is used by default when the submission method is [[POST (HTTP)|POST]], but the result is submitted as the [[HTTP request]] body rather than being included in a modified URL.<ref name="html5" />