question: private boolean isIdChar ( int ch ) { return isAlpha ( ch ) || isDigit ( ch ) || ch == '.' || ch == '-' || ch == '_' || ch == ':' || Character . isLetter ( ch ) ; }
target:  From HTML 4.0 [4]     NameChar     ::=    Letter | Digit | '.' | '-' | '_' | ':' | CombiningChar | Extender [5]     Name     ::=    (Letter | '_' | ':') (NameChar) [6]     Names    ::=    Name (#x20 Name) [7]     Nmtoken    ::=    (NameChar)+ [8]     Nmtokens     ::=    Nmtoken (#x20 Nmtoken)