this bug is absurd: CSS backface-visibility not working on localhost?

this is weird:

same file开发者_运维问答 test.html works then I double click it from

file:///Applications/MAMP/htdocs/test.html

but when I open

http://localhost/test.html

the CSS rules

-webkit-backface-visibility: hidden;

is not working anymore... why??? what the heck? is not required any external file...the test.html has everything embedded in itself...this is weird