I think I have a virus
Those things are not viruses rather they are called Pop-up Ads. You'll face this pop-ups on almost all the browsers including Chrome, Firefox, Opera etc. These ads always try to install Malware, Bloatware apps on your phone when clicked.
There are two browsers which blocks ads successfully...
1 - Firefox (with extension AdBlock Plus installed)
2 - UC Mini (with speed-mode enabled)  

P.S : Your phone does not have a virus.