How do I turn on barcode scanner on Android?

Does Android have a code scanner on it?

I have read on many forums that when you press the back button on the phone it goes to the code scanner and it says that your device has a virus.

If this is true, why do we not get the notification? Does anybody know? That's the thing, we don't even have to press the back button. All we have to do is just tap the screen where the icon of the virus appears, and it pops up.

I don't know if it's like that in every phone, but that's what I've seen. And that's why I asked. I've tried this on my Droid 2 and I don't get any notification.

That's what I don't understand. How can a virus cause this to happen? What are they trying to say? And if you are able to get the notification why not everyone? That is what I don't understand.

Android can be infected with malware.

Where is my Google barcode?

After the last update, there seems to be a missing Google barcode in the search results, not only from a Google barcode or Google Adsense code, but also for my own domains (eg "") and my own sites. For example, I typed "" in the Google search bar and then saw nothing. Now it's the same for my own domains and my own sites.

I don't know if it's a problem with the last update of Firefox or the Google Adsense update. But there is no error message on my browser (Firefox 43).

I think it has something to do with a barcode in the search results. Is this some bug in the latest update of Firefox? Or does anybody know if it's possible to find the barcode somehow? There was a bug in the latest version of Firefox 43 which affected the rendering of search result snippets. This should now be fixed in the beta channel and Firefox 46 (current stable release as of writing) but you can get it by using the about:config page in Firefox and setting network.http.cors.enabled to true.