I used to keep getting a popup every couple of minutes in Firefox browser with the message- “you have chosen to open search which is a: application/json from google.co.in”. Firefox is updated Firefox v8.0 . This does not happen on IE or Chrome.
I tried to find solution to this online and I found others are also facing the same problem. Could not find a convincing solution though?
Start Firefox in Safe Mode
Some report that this is due to some add-on. So to find out if it is, try starting Firefox in Safe Mode. To start Firefox with add-ons disabled, click on “Help” in the Firefox menu bar, then click “Restart Firefox with Add-ons disabled”. See if that solves the problem.
If not, then it is not related to add-ons in your case.
Here is a thread on mozilla support site, if you'd like to have a look: