Mac Browser Extensions

[colinr]

Hello,

Whilst customizing my home copy of Phoenix I came across extensions - http://texturizer.net/phoenix/extensions.html

Some of these (especially Checky) would be really useful to me on my work Mac, question is do any of the Mac browsers support extensions and is there one like Checky?

I have at my disposal...
Netscape 7
Explorer 5
Opera 6
Chimera (Post 0.6 nightly build)
Mozilla 1.2.1

I cant see anything about extensions but I could well be overlooking something.

Thanks,
Colin