Detail: Tag and Attribute Names
- All tag and attribute names must start with an alphabetic character, an underscore ( _ ) or colon ( : )
- The name must not contain any whitespace
- space, tab, line feed, carriage return etc
- Punctuation characters are allowed in names
- Colon is used just to define the namespace
- Names cannot start with xml
- Names in XML are case sensitive
- <exam>, <ExaM>, <EXAM> are all different tags
