|Contents||One or more OPTION elements|
The OPTGROUP element defines a group of choices within a SELECT menu. OPTGROUP must contain one or more OPTION elements to define the actual choices.
The required LABEL attribute specifies the group label presented to the user. The LABEL should describe the group of choices available through the OPTGROUP's OPTIONs. Each OPTION generally uses a LABEL attribute as well to provide a shortened label that, together with the OPTGROUP's LABEL, gives a complete description of the option. An example follows:
<P>Which Web browser do you use most often? <SELECT NAME=browser> <OPTGROUP LABEL="Netscape Navigator"> <OPTION LABEL="4.x or higher"> Netscape Navigator 4.x or higher </OPTION> <OPTION LABEL="3.x">Netscape Navigator 3.x</OPTION> <OPTION LABEL="2.x">Netscape Navigator 2.x</OPTION> <OPTION LABEL="1.x">Netscape Navigator 1.x</OPTION> </OPTGROUP> <OPTGROUP LABEL="Microsoft Internet Explorer"> <OPTION LABEL="4.x or higher"> Microsoft Internet Explorer 4.x or higher </OPTION> <OPTION LABEL="3.x">Microsoft Internet Explorer 3.x</OPTION> <OPTION LABEL="2.x">Microsoft Internet Explorer 2.x</OPTION> <OPTION LABEL="1.x">Microsoft Internet Explorer 1.x</OPTION> </OPTGROUP> <OPTGROUP LABEL="Opera"> <OPTION LABEL="3.x or higher">Opera 3.x or higher</OPTION> <OPTION LABEL="2.x">Opera 2.x</OPTION> </OPTGROUP> <OPTION>Other</OPTION> </SELECT> </P>
OPTGROUP is not well supported by current browsers, but its design allows authors to use it today without sacrificing compatibility with non-supporting browsers. Supporting browsers will render the preceding example using the LABEL attribute of OPTION to provide just the version number, along with the OPTGROUP's LABEL, which gives the full name of the application. This allows a compact display with easy-to-use cascading menus.
Non-supporting browsers will ignore the OPTGROUP elements and LABEL attributes, providing the full name and version for each choice. Thus authors can fully use OPTGROUP despite its lack of browser support.
Note that, in HTML 4.0, OPTGROUP is limited to containing only OPTION elements, thus preventing nested OPTGROUPs with multi-level cascades. Future versions of HTML may add support for nested option groups.
The boolean DISABLED attribute makes the option group unavailable. The options of a disabled option group cannot be selected by the user and are never submitted with the form.