Google announced , Chrome 81 will begin to phase out the use of user agent string Chrome browser.
The user agent string (user agent string, referred to as "UA string") is sent to the browser starts a text website connection. It contains information about the type of browser, the rendering engine details and operating systems, including. For example, Windows UA string for Firefox 10 as follows:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/72.0
UA string in the 1990s was developed as part of the Netscape browser, and is still in use. According to Google's assessment , up to 90% of the site to read and use the browser user agent in a variety of ways. It was originally designed to allow the server to ensure that the user receives is optimized for a particular browser requirements page. Now available, the user agent sniffing has become a source of a lot of privacy issues, a large number of advertisers have used the string to track and identify website visitors the way.
Not only is privacy issues, UA string also brought other problems. Not long ago, a browser based on Chromium Vivaldi forge its user agent string to be displayed as Chrome, adding that the reason is to solve some unexplained errors that will occur only when Vivaldi identified in the browser.
To address these issues, Google said it planned to freeze the entire standard by phasing out the importance of UA string in Chrome. In the long run, Google's plan is to put all Chrome UA string in the same common values, these common values will not disclose too much information about the user.
Google for the current process step UA string like this:
- Chrome 81 (mid-March 2020) - display a warning so that developers can adjust their sites to read the code for UA string in Chrome Web console;
- Chrome 83 (early June 2020) - Freeze Chrome browser version UA string, and unified operating system version of universal value;
- Chrome 85 (mid-September 2020) - UA unified desktop operating system string, as a universal value of the desktop browser; unified mobile operating system / equipment string universal value.
As early as 2017, Apple will attempt to completely freeze the user agent string in Safari. But because it is too strict, causing developers can not get the information you need, then failed.
The Google proposed a compromise, abandoned before the user agent string, Chrome will introduce a feature called " user agent client prompt" (UA-CH) new features may be required to provide to the network developer information while respecting user privacy. Last August, Google announced the "Privacy sandbox" program, aimed at developing a set of open standards, to enhance network privacy radically new "client prompt" mechanism has been started in the project.
At present, Chrome 81 has been in the Canary stage, and plans to release in March this year. Apple (Safari), Microsoft (Edge) and Mozilla (Firefox) also expressed support for the proposal, and is likely to continue to follow the same way to handle user agent string.