[eterm]

It's 8! (8 factorial) which is 40320.

This is 127,286,426,869 (~128bn) times smaller than 92^8.

Edit: Note that if you have a repeated character in your 8 charcter password then the number of permutations of the set of 8 (7 distinct) characters is further halved to 20,160.

[Klathmon]

And just by doubling the amount of selectors you could always check for a repeated character! (AKA [value$=aa], [value$=bb], etc...)