[Mozilla Enterprise] What is Compatibility Mode?

[John R. Sweet]

I am trying to access the online property data on this site:
https://treasurer.bathcountyva.org/applications/txapps/PropCardsIndex.htm

This link brings up an otherwise blank page with the line:
"To access this site, please acknowledge the following statement:"
The statement box is blank and the "Accept" button below it is inactive.

I wrote to the owner of the site asking, "What do I need to do?"

Following is the result of that inquiry.  Can anyone suggest a solution?  Thanks,  JRS
__________________________________________________

> On 05/21/2018 09:42, agrimm at bathcountyva.org wrote:
>> You may need be compatibility mode for the site. I clicked the link
>> and came up to "accept the terms". after clicking accept the terms
>> you will be directed to the options for property cards.
>
> On 05/21/2018 11:32, John R. Sweet wrote:
>Ummmmm, sorry but I have no clue what that means.  I use Firefox and have enabled cookies for
> this site.  What is "compatibility mode"?
>
> Thanks,    JRS

On 05/21/2018 15:01, agrimm at bathcountyva.org wrote:
> under tools dropdown on the left top of your screen choose compatibility view and add website.

On 05/21/2018 15:52, John R. Sweet wrote:
FF Tools menu does not offer that choice. I also looked under Tools | Options and it is not there either. I guess I'm out of luck. Oh well, thanks for trying. JRS