You need to have OpenSSL optional package installed, a Haiku–hybrid or Haiku–gcc4 build and BeZilla–gcc4.

Warning: before installing, be aware that
after installing, you won't be able to visit the standard mode of gmail.com;
the fonts will slightly change;
following links from swf content and fullscreen mode isn't supported;
shared memory module is not implemented yet and many swf files won't play correctly.