Hi, as far as I know, one should use xhtml to make an epub book. Can I use html to make an epub? Thanks for your help.

Hi, as far as I know, one should use xhtml to make an epub book. Can I use html to make an epub? Thanks for your help.

yes, you can start with HTML. Give Sigil a go, it will help you take your HTML and get it in shape.

Thanks for your help, JS.

It is not exactly true. It must be XHTML. However, Sigil will convert it to XHTML to certain extent. There are some differences which must be kept in mind. One of the major one is the usage of name in anchors and so. It should be changed to id. That specific difference can cost quite some headache if you don't know.
Also, use the validation button in Sigil. It will help you.

It is not exactly true. It must be XHTML. However, Sigil will convert it to XHTML to certain extent.

It might be slightly confusing because the file extensions aren't changed by Sigil. They will still show as .html but the requirements of XHTML are met...header, proper closing of tags, use of quotes within the tag, and the use of ID like Toxaris mentioned.

The .html extension does not cause the ePub to fail validation AFAIK.

Cheers

It is so similar that you can get hooked when you run a validating program. Tags, for instance, must be self closing.

You can check out:
http://www.w3schools.com/html/html_xhtml.asp