It does not say that it supports mobile devices/browsers, but it seems to work pretty well.

The major issue with mobile support is smartphones being narrow. Showing 26 letters worth of tabs is too wide for a smartphone.

Is there anyway to have the tabs "wrap" around, so instead of the following all on one line:

A B C D E F G H I J K L M N O ...

it could look like this:

A B C D E F G

H  I J  K L M N

O P Q R  S T U 

V W X  Y Z ...

(I guess you could break your list into 5 separate lists and stack them, but that defeats the purpose of taking an existing list.)