The User Agent Switcher extension is a secret agent in disguise for Firefox. You can put on your IE hat and slip past virtual bouncers into Internet Explorer-only websites; blend in as an iPhone and explore the web’s mobile underbelly; or flash your fake Google ID card and get the V.I.P. treatment.
User Agent Switcher is simple, yet powerful. It adds a toolbar button that you can use to toggle between different user agent strings. User Agent Switcher overrides Firefox’s default user agent, tricking websites into thinking you’re using a different browser.
What’s a User Agent?
Your browser sends its user agent, which contains the browser’s version and operating system, whenever you connect to a website. Websites can detect the browser you’re using and serve different content — this is why iPhone and Android users see special mobile websites when they browse the web.
Like most Firefox add-ons, User Agent Switcher is available in Firefox’s add-ons gallery. After it’s installed, you can right-click your toolbar, select Customize and put the User Agent Switcher button anywhere you like.
Crash Internet Explorer’s Party
It’s happened to all of us, although it happens less often these days. You click a link expecting to see a web page, but you’re locked out. “This website requires Internet Explorer,” it says. Does it really require Internet Explorer? Not usually. With the User Agent Switcher extension, you can disguise Firefox as Internet Explorer and slip right in.
Here’s a website from the IE-only hall of shame:
Yuck. Let’s click the User Agent Switcher menu and pretend to be Internet Explorer.
Now we can slip right in. As far as the website is concerned, we’re using Internet Explorer.
Remember to switch your user agent back after you’re done. You wouldn’t want to inflate Internet Explorer’s usage statistics by pretending to be IE everywhere, would you?
This won’t help if the website really is IE-only. Websites that use ActiveX controls are out; those only run in Internet Explorer. Try the IE Tab extension if you encounter one of those sites — IE Tab runs Internet Explorer itself in a Firefox tab.
Explore the Mobile Web
Select the iPhone user agent and you’ll appear as a mobile device. Websites won’t always function like they would on a real iPhone, but you’ll still see the mobile version of the website.
Here we have YouTube’s mobile site running on our “iPhone”:
And here’s Gmail on our makeshift iPhone:
This is a convenient way to test mobile websites, although you’ll still have to test them on a real device. If you have a mobile device, you can do the reverse and see full versions of websites in the palm of your hand.
See What Google Sees
Sometimes a website wants to force you to create an account. You’ll click a link, even from Google, and see a sign-in or registration page.
These websites don’t want to hide their content from Google, so they often allow full access to Google’s web crawler. You can select the Googlebot user agent string and Firefox will put on its best Google disguise.
It’s possible for a website to say “Hey, look at your IP address — you’re not really Google!” But, in practice, few websites do. You shouldn’t use this method to trick your way into accessing paid content, but it’s a good alternative to BugMeNot for getting past annoying registration screens.
Get More User Agents
User Agent Switcher comes with a few popular user agents, but you can get user agents for any browser or device you can think of. Use the “Download lists of user agents to import” link in the extension’s options window to find other lists of user agents.
After downloading a list in XML format, click the Import button and import the user agents from the XML file. Or, use the New button to add and customize individual user agent strings.
I’m sure there are other clever uses for the User Agent Switcher extension — what do you use it for?