Can the select option value be of different types?

Answer 1

There are no limits real to the type of data that can be set in the value attribute of the option element. Characters with special meaning in HTML do, of course, need to be represented by the appropriate entities (& as & for example (although the one in the question meets the "followed by a space character" exception to the rule)).

The attribute is defined as containing CDATA:

— http://www.w3.org/TR/html4/interact/forms.html#h-17.6

CDATA is a sequence of characters from the document character set and may include character entities. User agents should interpret attribute values as follows:

• Replace character entities with characters,
• Ignore line feeds,
• Replace each carriage return or tab with a single space.

User agents may ignore leading and trailing white space in CDATA attribute values (e.g., " myval " may be interpreted as "myval"). Authors should not declare attribute values with leading or trailing white space.

For some HTML 4 attributes with CDATA attribute values, the specification imposes further constraints on the set of legal values for the attribute that may not be expressed by the DTD.

— http://www.w3.org/TR/html4/types.html#type-cdata

The specification doesn't impose additional limits for the option element's value attribute.