Do I need to declare XML on a page using the XHTML doctype?
问题 I've been seeing some conflicting information that an XHTML document must also declare itself as XML. <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> However, in other places I'm seeing (including w3.org) that the DOCTYPE must be the first tag declaration. Since W3 says it, it must be true. However, I probably have some pages/apps lying about that are following the first method.