Browser User Agent
What Is a Browser’s User Agent? – HowToGeek
Your browser sends its user agent to every website you connect to. We’ve written about changing your browser’s user agent before – but what exactly is a user agent, anyway?
A user agent is a “string” – that is, a line of text – identifying the browser and operating system to the web server. This sounds simple, but user agents have become a mess over time.
The Basics
When your browser connects to a website, it includes a User-Agent field in its HTTP header. The contents of the user agent field vary from browser to browser. Each browser has its own, distinctive user agent. Essentially, a user agent is a way for a browser to say “Hi, I’m Mozilla Firefox on Windows” or “Hi, I’m Safari on an iPhone” to a web server.
The web server can use this information to serve different web pages to different web browsers and different operating systems. For example, a website could send mobile pages to mobile browsers, modern pages to modern browsers, and a “please upgrade your browser” message to Internet Explorer 6.
Examining User Agents
For example, here’s Firefox’s user agent on Windows 7:
Mozilla/5. 0 (Windows NT 6. 1; WOW64; rv:12. 0) Gecko/20100101 Firefox/12. 0
This user agent tells the web server quite a bit: The operating system is Windows 7 (code name Windows NT 6. 1), it’s a 64-bit version of Windows (WOW64), and the browser itself is Firefox 12.
Now let’s take a look at Internet Explorer 9’s user agent, which is:
Mozilla/5. 0 (compatible; MSIE 9. 0; Windows NT 6. 1; WOW64; Trident/5. 0)
The user agent string identifies the browser as IE 9 with the Trident 5 rendering engine. However, you might spot something confusing – IE identifies itself as Mozilla.
We’ll come back to that in a minute. First, let’s examine Google Chrome’s user agent, too:
Mozilla/5. 1; WOW64) AppleWebKit/536. 5 (KHTML, like Gecko) Chrome/19. 0. 1084. 52 Safari/536. 5
The plot thickens: Chrome is pretending to be both Mozilla and Safari. To understand why, we’ll have to examine the history of user agents and browsers.
The User Agent String Mess
Mosaic was one of the first browsers. Its user agent string was NCSA_Mosaic/2. Later, Mozilla came along (later renamed Netscape), and its user agent was Mozilla/1. Mozilla was a more advanced browser than Mosaic – in particular, it supported frames. Web servers checked to see that the user agent contained the word Mozilla and sent pages containing frames to Mozilla browsers. To other browsers, web servers sent the old pages without frames.
Eventually, Microsoft’s Internet Explorer came along and it supported frames, too. However, IE didn’t receive web pages with frames, because web servers just sent those to Mozilla browsers. To fix this problem, Microsoft added the word Mozilla to their user agent and threw in additional information (the word “compatible” and a reference to IE. ) Web servers were happy to see the word Mozilla and sent IE the modern web pages. Other browsers that came later did the same thing.
Eventually, some servers looked for the word Gecko – Firefox’s rendering engine – and served Gecko browsers different pages than older browsers. KHTML – originally developed for Konquerer on Linux’s KDE desktop – added the words “like Gecko” so they’d get the modern pages designed for Gecko, too. WebKit was based on KHTML – when it was developed, they added the word WebKit and kept the original “KHTML, like Gecko” line for compatibility purposes. In this way, browser developers kept adding words to their user agents over time.
Web servers don’t really care what the exact user agent string is – they just check to see if it contains a specific word.
Uses
Web servers use user agents for a variety of purposes, including:
Serving different web pages to different web browsers. This can be used for good – for example, to serve simpler web pages to older browsers – or evil – for example, to display a “This web page must be viewed in Internet Explorer” message.
Displaying different content to different operating systems – for example, by displaying a slimmed-down page on mobile devices.
Gathering statistics showing the browsers and operating systems in use by their users. If you ever see browser market-share statistics, this is how they’re acquired.
Web-crawling bots use user agents, too. For example, Google’s web crawler identifies itself as:
Googlebot/2. 1 (+)
Web servers can give bots special treatment – for example, by allowing them through mandatory registration screens. (Yes, this means that you can sometimes bypass registration screens by setting your user agent to Googlebot. )
Web servers can also give orders to specific bots (or all bots) using the file. For example a web server could tell a specific bot to go away, or tell another bot to only index certain areas of the website. In the file, the bots are identified by their user agent strings.
All major browsers contain ways to set custom user agents, so you can see what web servers send to to different browsers. For example, set your desktop browser to a mobile browser’s user agent string and you’ll see the mobile versions of web pages on your desktop.
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How to detect the user browser ( Safari, Chrome, IE, Firefox and …
The browser on which the current page is opening can be checked using userAgent property of the navigator object is used to return the user-agent header string sent by the browser. This user-agent string contains information about the browser by including certain keywords that may be tested for their presence of a specific user-string can be detected using the indexOf() method. The indexOf() method is used to return the first occurrence of the specified string value in a string. If the value does not come up in the string, “-1” is geek! The constant emerging technologies in the world of web development always keeps the excitement for this subject through the roof. But before you tackle the big projects, we suggest you start by learning the basics. Kickstart your web development journey by learning JS concepts with our JavaScript Course. Now at it’s lowest price ever! The user-agent string of the browser is accessed using the erAgent property and then stored in a variable. The presence of the strings of a browser in this user-agent string is detected one by tecting the Chrome browser: The user-agent of the Chrome browser is “Chrome”. This value is passed to indexOf() method to detect this value in the user-agent the indexOf() method would return a value that is greater than “-1” to denote a successful search, the “greater-than” operator is used to return a boolean value on whether the search was successful or not. This is done for all the following chromeAgent = dexOf(“Chrome”) > -1;Detecting the Internet Explorer browser: The user-agent of the Internet Explorer browser is “MSIE” or “rv:”. Both these values are passed to the indexOf() method to detect this value in the user-agent string and the result of both them are used with the OR IExplorerAgent = dexOf(“MSIE”) > -1 || dexOf(“rv:”) > -1;Detecting the Firefox browser: The user-agent of the Firefox browser is “Firefox”. This value is passed to indexOf() method to detect this value in the user-agent firefoxAgent = dexOf(“Firefox”) > -1;Detecting the Safari browser: The user-agent of the Safari browser is “Safari”. This value is passed to indexOf() method to detect this value in the user-agent additional check is required in the case of the Safari browser as the user-agent of the Chrome browser also includes the Safari browser’s user-agent. If both the user-agents of Chrome and Safari are in the user-agent, it means that the browser is Chrome, and hence the Safari browser value is safariAgent = dexOf(“Safari”) > -1;if ((chromeAgent) && (safariAgent)) safariAgent = false;Detecting the Opera browser: The user-agent of the Opera browser is “OP”. This value is passed to indexOf() method to detect this value in the user-agent additional check is also required in the case of this browser as the user-agent of the Opera browser also includes the Chrome browser’s user-agent. If both the user-agents of Chrome and Opera are in the user-agent, it means that the browser is Opera, and hence the Chrome browser value is operaAgent = dexOf(“OP”) > -1;if ((chromeAgent) && (operaAgent)) chromeAgent = false;Example:
GeeksforGeeks
How to detect Safari, Chrome, IE, Firefox and Opera browser using JavaScript?
Click on the button to detect the current browser
Is Safari?
Is Chrome?
Is Internet Explorer?
Is Firefox?
Is Opera browser?
Output:
What are the latest user agents for Firefox? – WhatIsMyBrowser.com
Mozilla Firefox runs on a several different operating systems and the user agent structure for each varies a bit.
Here we have the latest user agents for Firefox on Windows, macOS, Linux, iOS and Android.
Please note that these are very “stock-standard” Firefox user agents and certainly don’t reflect the wide variety of possible Firefox user agents that exist today. These user agents don’t show anyextra addons, network providers or anything else customised or particular; these are just the standard user agents.
Explore our huge user agent listing, download our user agents database, (or you can search it) if you’re curious about other user agents.
Get latest user agents for Firefox via API
Our Web Browser/Operating System Version Numbers API endpoint will provide you with the latest user agents for all sorts of popular web browsers and operating systems.
Latest Firefox on Desktop User Agents
Platform
Latest Firefox User Agents
Firefox on Windows
Mozilla/5. 0 (Windows NT 10. 0; Win64; x64; rv:93. 0) Gecko/20100101 Firefox/93. 0
Firefox on Macos
Mozilla/5. 0 (Macintosh; Intel Mac OS X 11. 6; rv:93. 0
Firefox on Linux
Mozilla/5. 0 (X11; Linux i686; rv:93. 0
Mozilla/5. 0 (Linux x86_64; rv:93. 0 (X11; Ubuntu; Linux i686; rv:93. 0 (X11; Ubuntu; Linux x86_64; rv:93. 0 (X11; Fedora; Linux x86_64; rv:93. 0
Latest Firefox on iOS User Agents
Firefox on Iphone
Mozilla/5. 0 (iPhone; CPU iPhone OS 11_6 like Mac OS X) AppleWebKit/605. 1. 15 (KHTML, like Gecko) FxiOS/38. 0 Mobile/15E148 Safari/605. 15
Firefox on Ipad
Mozilla/5. 0 (iPad; CPU OS 11_6 like Mac OS X) AppleWebKit/605. 15
Firefox on Ipod
Mozilla/5. 0 (iPod touch; CPU iPhone OS 11_6 like Mac OS X) AppleWebKit/604. 5. 6 (KHTML, like Gecko) FxiOS/38. 15
Latest Firefox on Android User Agents
Firefox (Standard)
Mozilla/5. 0 (Android 12; Mobile; rv:68. 0) Gecko/68. 0 Firefox/93. 0
Firefox on Lg
Mozilla/5. 0 (Android 12; Mobile; LG-M255; rv:93. 0) Gecko/93. 0
Latest Firefox Extended Support Release (ESR) on Desktop User Agents
Mozilla/5. 0; Win64; x64; rv:91. 0) Gecko/20100101 Firefox/91. 6; rv:91. 0 (X11; Linux i686; rv:91. 0 (Linux x86_64; rv:91. 0 (X11; Ubuntu; Linux i686; rv:91. 0 (X11; Ubuntu; Linux x86_64; rv:91. 0 (X11; Fedora; Linux x86_64; rv:91. 0
Special notes
Major release version numbers only
For a while now, Firefox’s user agent has only included the “major release” version number in the user agent; so while a copy of Firefox might actually be version 61. 0. 2, it would only be reported as version “61. 0” in the user agent.
Experiment with different user agents
You can use our User Agent Parser page to try out different user agent varieties, or to test if your user agent switcher is working properly.
Database of user agents
If you’re interested in our database of many millions of user agents, please check out our API which provides access to our user agent database. You can perform very detailed and specific queries on it to find user agents that match your exact criteria – version numbers, hardware types, platforms and so on.
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Frequently Asked Questions about browser user agent
How do I find my browser user agent?
The user-agent string of the browser is accessed using the navigator. userAgent property and then stored in a variable. The presence of the strings of a browser in this user-agent string is detected one by one. Detecting the Chrome browser: The user-agent of the Chrome browser is “Chrome”.Nov 15, 2019
Is Firefox a user agent?
Mozilla Firefox runs on a several different operating systems and the user agent structure for each varies a bit. … Please note that these are very “stock-standard” Firefox user agents and certainly don’t reflect the wide variety of possible Firefox user agents that exist today.
What is user agent in Safari?
A browser’s user agent string (UA) helps identify which browser is being used, what version, and on which operating system. … Like all other browsers, Chrome for Android sends this information in the User-Agent HTTP header every time it makes a request to any site.Feb 28, 2014
