SEF Advanced .html extension

How do I have all my pages end with .html instead of .html/ ?

URLs will either end with .html or a /, never with .html/
If you don't want the .html suffix, disable it in global configurations (for Joomla 1.5) or in SEF Advance configuration (for Joomla 1.0).

P.S. Please state the version in your posts.

This is for a 1.0.15 website and the urls currently are contact/ and I would like them to display as contact.htm or contact.html. Please advise. Thanks

Just enter .htm or .html in the "Suffix" field of SEF Advance configurations and save.

Hello

Is it possible to have no "/" at the end of the urls when choosing nothing in the suffix field?

Thanks

No, if you leave it empty you would end up with trailing slash. If you think it would be beneficial not to have any suffix I could consider it for next versions maybe.