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Is it possible to modify the user agent from within a chrome extension?

I am developing an extension for web developers (yes I'm aware of Chromes own extension for this).

Any ideas?

GV1
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3 Answers3

5

Example code changing the User-Agent for an Android one.

var MOBILE_CHROME_USER_AGENT = 'Mozilla/5.0 (Linux; U; Android-4.0.3; en-us; Galaxy Nexus Build/IML74K) AppleWebKit/535.7 (KHTML, like Gecko) CrMo/16.0.912.75 Mobile Safari/535.7';
chrome.webRequest.onBeforeSendHeaders.addListener(
    function(details) {
        for (var i = 0; i < details.requestHeaders.length; ++i) {
            if (details.requestHeaders[i].name === 'User-Agent') {
                details.requestHeaders[i].value = MOBILE_CHROME_USER_AGENT;
                break;
            }
        }
        return {requestHeaders: details.requestHeaders};
    }, {urls: ['<all_urls>']}, ['blocking', 'requestHeaders']);
Ivan Castellanos
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  • Works great! Be sure to include `webRequest` and `webRequestBlocking` in your manifest permissions, otherwise chrome.webRequest will be undefined – theicfire Oct 11 '19 at 23:18
  • Some websites also look for javascript user agents. See https://stackoverflow.com/questions/23202136/changing-navigator-useragent-using-chrome-extension to change that in extensions as well – theicfire Oct 12 '19 at 00:45
2

The WebRequest API is no longer experimental; You can read all about it at its new home: chrome.webRequest

and yes you can use it to alter the User-Agent header.

Ayoub Kaanich
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0

There's experimental WebRequest API for these purposes. You can prevent URL requests, change request headers etc. Of course you can't yet upload your extension to Chrome Web Store if your code uses experimental features of Chrome extensions.

Dmitrii Sorin
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