What is the best browser for an ipad 3?

Look at these and read the descriptions.

Here are a few third party web browsers that I know are STILL being updated and supported on iOS 9.

Perfect Web browser

iCab Mobile Web browser

Dolphin Web browser

Aloha Web browser

Maven Web browser

Maxthon Web browser

Opera Web Browser

Perfect Web Browser JUST had a very recent update to iOS 11, but the older last version update is still available here and had its last older iOS update this past April 2018.

Perfect® Browser+ (Legacy) by AppSimply

https://itunes.apple.com/us/app/perfect-browser-legacy/id373916467?mt=8

I use Perfect Web browser and iCab mobile Web browsers on all of my iDevices.

Good Luck to You!