Editing User-Agent header (section)

== User agent spoofing == <!-- courtesy note per [[WP:RESECT]]: [[User agent spoofing]] links here -->
The popularity of various Web browser products has varied throughout the Web's history, and this has influenced the design of websites in such a way that websites are sometimes designed to work well only with particular browsers, rather than according to uniform standards by the [[World Wide Web Consortium]] (W3C) or the [[Internet Engineering Task Force]] (IETF). Websites often include code to detect browser version to adjust the page design sent according to the user agent string received. This may mean that less-popular browsers are not sent complex content (even though they might be able to deal with it correctly) or, in extreme cases, refused all content.<ref>[http://www.anybrowser.org/campaign/ Burstein complaining "...&nbsp;I've been rejected until I come back with Netscape"]</ref> Thus, various browsers have a feature to ''cloak'' or ''spoof'' their identification to force certain server-side content. For example, the Android browser identifies itself as [[Safari (web browser)|Safari]] (among other things) in order to aid compatibility.<ref>{{cite web|url=http://androidcommunity.com/forums/f8/android-browser-reports-itself-as-apple-safari-4701/ |title=Android Browser Reports Itself as Apple Safari |access-date=August 9, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110806170335/http://androidcommunity.com/forums/f8/android-browser-reports-itself-as-apple-safari-4701/ |archive-date=August 6, 2011 }}</ref><ref>{{cite web|title=User Agent String explained: Android Webkit Browser|url=http://www.useragentstring.com/Android%20Webkit%20Browser_id_18070.php|publisher=UserAgentString.com|access-date=29 July 2012|quote=Mozilla/5.0 (Linux; U; Android 2.2; en-sa; HTC_DesireHD_A9191 Build/FRF91) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1|archive-date=4 May 2012|archive-url=https://web.archive.org/web/20120504175934/http://www.useragentstring.com/Android%20Webkit%20Browser_id_18070.php|url-status=dead}}</ref>

Other HTTP client programs, like [[download manager]]s and [[offline browser]]s, often have the ability to change the user agent string.

A result of user agent spoofing may be that collected [[Usage share of web browsers|statistics of Web browser usage]] are inaccurate.