Converting from traditional HTML to XHTML 1.0 Transitional is easy, as long as you work carefully and observe the following rules:
1. Open with the proper DOCTYPE & Namespace
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd “>
2. Write all tags in lowercase
<title>XHTML Rules</title>
3. Quote all attribute values
src=”xyz.png” and not src=xyz.png
4. Close all tags
<p>Some Text</p>
5. Close “empty” tags, too
<img src=”xyz.png” />