User Agent

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What Does User Agent Mean?

A user agent (UA) is a software element that acts on behalf of a user. However, the term user agent has also come to be associated with a header string in HTTP and related technologies that help a hosting server identify the type of operating system and/or device requesting content.

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The use of user agents is a controversial topic because of UA requests for Web content and the creation of Web pages that handle various browsers in different ways. A movement to equalize access between browsers attempted to promote more broadly accessible design, but some sites are still designed with specific browsers or devices in mind. In general, the browser as UA is a key component of the Internet’s developmental timeline. It continues to change as desktop and laptop computers give way to mobile devices for Internet viewing.

Techopedia Explains User Agent

A broader UA definition includes Web crawlers, Web bots and other technologies. However, a Web browser is a simple example of a common UA setup. Here, the browser acts as the UA, where the user actively controls the browser. The browser issues certain UA strings that show the specific technology used to access a site, page or other content. For example, a UA string from a Firefox browser would include the word Mozilla, as well as version data and other details.

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Margaret Rouse
Technology Specialist
Margaret Rouse
Technology Specialist

Margaret is an award-winning writer and educator known for her ability to explain complex technical topics to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles in the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret’s idea of ​​a fun day is to help IT and business professionals to learn to speak each other’s highly specialized languages.