‘80% of the browsers contains 20% of the bugs and the rest 80% of the bugs will show up in the remaining 20% of the browsers’.
So you need to now test those 20% of the bugs for finding and fixing those 80% of the bugs.
Start testing by prioritizing the browsers based on the relevance of the browsers and then going on to the least relevant browser.
If your audience is using Safari the maximum then you need to test it for safari first. Then followed by the browsers which are the least used.
This is basically done in the descending order of market share.
What’s the point of testing your webapp on the browser which is being used by 0.05% of the population? So, your testing needs to make sense here.
Based on browser prioritizing decide for yourself, which browsers makes the most sense to you and which browsers makes the least sense.