CSS: Is Helvetica the default 'sans-serif' font on Mac and Arial the default sans-serif font on Windows?

Question

I have a lot of CSS that does the following:

font-family: Helvetica, Arial, sans-serif;

It my understanding that Helvetica is the default sans-

Answer 1

Helvetica is sometimes the default sans on Mac, but to be honest it's not a great screen font.

Geneva, Lucida Sans, and Trebuchet MS are good alternatives.