what is the meaning of virtually addressed physically tagged cache ?

Question

I am confused over one point that do we look up into cache before address translation or simultaneously , In the below link it is mentioned that it " caches are typically indexed with the virtual address, allowing the indexing to begin before address translation is completed. "

http://superuser.com/questions/745008/whats-the-difference-between-physical-and-virtual-cache

Now the point of confusion is that how come only page offset is used to index  a cache , and if hit occurs then what will happen to the physical address generated by MMU , since the cache is indexed before address translation only .