What is the best way to alter the html of the forums table on the index page?
For the boards?
It will depend on what you want to do.
Could you provide more details like your SMF version?
Ideally, for 2.1 you could edit the css to accomplish most changes.
It is smf 2.1. I was wondering if it is at all possible to alter class names and such for the forum list instead of altering the look with just css, just alter the html for the forums listed on the index page.
Why do you want to do this? Changing class names just means you will need to change the CSS to take account of the new class names.
What, exactly, are you trying to achieve? Think it through, and be specific.
I mean, sure, almost anything is possible if you know how to code it. :)
but the question Antechinus asked is really the key here.
WHAT are you trying to accomplish
(and the subquestion would be and why do you think that changing the html markup and re-writing all the CSS is better than using the existing markup and changing the CSS?)