How to pass argument to index(arg='') ?

Thank you Dmyers,
Actually, the reason i asked because, it was working on my previous hosting server. But when I moved to new hosting with the same code, It just didn't work. I would think I might miss some configure or not.
I put the tail .html to the end of url.
Eg http://myweb.com/home.html which would view myself profile. Home is a controller and argument is id. This case it is default from login session for my own id.
Then when I view my friend profile it pass id to index($id='') the url is http://myweb.com/home/2.html
But this does not work anymore, I need to put longer like http://myweb.com/home/index/2.html
When to edit it will be like http://myweb.com/home/edit/2.html. I feel it jump away from a profile, where actually working on id 2.
Anyway, it is not a big deal, just find out if there is possibility to make it works witout having method /index/ in the url.