Google Chrome and WebKit Update User Agent String, Following IE and Firefox

By on April 1st, 2011 10:00 GMT

The Chrome team has announced that there will be changes to the Chrome and Chromium User Agent (UA) string, to bring them in line with Internet Explorer 9 and Firefox 4. What's more, the WebKit UA has also undergone the same updates.

The changes are not great, mostly housekeeping stuff which removes some of the unnecessary bits that have gathered over the years, but if you're site relies on the user agent for some specific functionality you should probably check out what's new and what has been removed.

"When websites want to know what browser you're using, they often examine the 'user agent', or 'UA' string. This is a string that provides information about what browser and operating system you're using," Peter Kasting, Software Engineer at Google, writes.

"Beginning with Chrome 11, we're making some changes to our UA string, which can affect website compatibility," he announced.

Here's what the current UA string in Chrome 10 looks like:

Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.204 Safari/534.16

And here is the updated one:

Mozilla/5.0 (Windows NT 6.0; WOW64) AppleWebKit/534.24 (KHTML, like Gecko) Chrome/11.0.696.16 Safari/534.24

There are several changes. On the Windows platform, the first 'Windows' identifier is gone since it's redundant as the Windows version is supplied anyway.

Next to be removed is the 'U' token which indicates SSL encryption strength. Back in the prehistoric ages of the internet, i.e. a decade ago, the US prohibited software that was going to be used internationally to have anything stronger than 40-bit encryption. Today, all browsers ship with 128-bit encryption so that token is no longer needed.

There are now identifiers for 64-bit versions of Windows. Chrome doesn't have a native 64-bit build and it doesn't plan on making one anytime soon, but it has added the identifiers just in case, namely "Win64; x64" and "Win64; IA64".

The locale token has been removed and Chrome recommends that websites use alternative means of determining a user's location such as the 'Accept-Language' HTTP header.

These changes have first been introduced by the Internet Explorer team. With the most popular browser leading the way, everyone got on board. Mozilla introduced the same changes in the Firefox 4 beta stage and Chrome is doing it now. The same changes have now become available in WebKit as well.

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