A user agent is a computer program representing a person, for example, a browser in a Web context.
Besides a browser, a user agent could be a bot scraping webpages, a download manager, or another app accessing the Web. Along with each request they make to the server, browsers include a self-identifying User-Agent HTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.
Spam bots, download managers, and some browsers often send a fake UA string to announce themselves as a different client. This is known as user agent spoofing.
A typical user agent string looks like this: "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0".
To do so, simply visit our project on the Debate hosted instance, create an account and either select an existing language or add a new one to get going. This way it becomes much easier for me to keep track of reported issues and get back to you if additional information is needed to help you.
This feature is useful for SEO professionals, for example, to identify issues with cloaking which is against Google’s Webmaster Guidelines or auditing websites which has different look depending on the device. User agent is an HTTP request header string identifying browser, application, operating system which connects to the server.
Get our daily newsletter from SEJ's Founder Loren Baker about the latest news in the industry! If you want an item added, then post in this thread, and include the following information: device brand, model/model number (if mobile UA); full user agent string; the browser name/version number, if relevant.
Mobile devs, if you have a device/OS/browser you want added, please post here, note what device it is plus the full user agent string, thanks. 2.2.2 – December 6 2010 – 3 new search bots added: Bing, Exact, and Google Web Preview.
I've seen examples of URLs being planted in the string itself, and I understand how some users might wish to spoof their browser, but are there any other legitimate uses? There's lots of uses for user agent switching as long as there are lame website makers who do silly Internet Explorer only user agent detection when the site runs fine on Firefox.
For testing your own scripts too it's pretty useful, to make sure you didn't forget anything if you are doing for example CSS user agent detection. We made this one to test our PHP browser detection script because there was a certain point where we had some awful bugs in it that would have been caught if had used the useragentswitcher.
Personally, I'd turn the question around and ask if it is a legitimate use of HTML and the Hyper Text Transfer Protocol in general to make a site that only works in one of the technically the worst browsers out there at the moment, MSI. Personally, I'd turn the question around and ask if it is a legitimate use of HTML and the Hyper Text Transfer Protocol in general to make a site that only works in one of the technically the worst browsers out there at the moment, MSI. In the wireless/handheld world, using the UA string to determine the capabilities of a device and send appropriate information used to be a requirement if you wanted anything beyond plain text.
Today most handheld browsers support some level of CSS and most of HTML 4.01 (or XHTML), but if you are still trying to squeeze the most out of a user's device capabilities, the UA string may tell you that the device only supports 2-bit B&W images, etc... Paul, I use it for testing all sorts of service that sniff UA strings, such as “mobile” versions of various websites (CNN, Google, Yahoo, etc...).
The access log data would be useful if you feel like posting the various user agent strings from it, I almost never see mobiles in my stats. I had that page bookmarked too, too bad the site is gone, but I saved that, got a link to a wireless XML data file on Sourceforge.
That's a pretty complete list, but the annoying thing is that there is absolutely no consistency in user agent patterns, none. If you can provide an unto date real world list that would be great though, as you can see, that XML file is very big , and I'm sure most of those aren't actually in active use.