This element is used to group together option elements within a select form control. They are particularly useful when the select list becomes very long, but it is not possible (or rather does not make sense) to split the list into separate form controls.
<optgroup class="class name(s)" dir="ltr | rtl" disabled id="unique identifier" label="text"‡ lang="language code" style="style information" title="text" > </optgroup>
‡ = Required attribute
** = Transitional only
Explanation of attributes
class: used to state which class(es) the element belongs to. It is possible to indicate more than one class for an element by separating each class name with a space character. This attribute is normally used in combination with a stylesheet in order to associate the elements with particular styles defined within the stylesheet.
dir: used to set the direction of the text in combination with the language set in the lang attribute. The available values are "ltr" (left to right) and "rtl" (right to left), with the default value being "ltr".
disabled: this attribute is used to disable an option group. This means that it cannot be selected by the user.
id: used to specify a unique alphanumeric identifier to the element. This is usually used in combination with stylesheets in order to apply a style to one particular instance of an element. Only one element, regardless of type, can be given a particular id.
label‡: this required attribute is used to specify a short label that is associated with the group of options. It may be displayed by the browser in a hierarchical style.
lang: used to indicate the language being used in the text contained within the element. The value of this attribute takes on the form of the ISO standard lanuage abbreviations found in RFC 3066. A list of these codes can be found on the ISO language codes page.
style: used to specify an inline style to apply to the element. The styles defined here override the styles declared in the header section.
title: used to define an advisory text that may be displayed as a tooltip when a mouse is used to hover over the element.
The following event handlers are defined for this element:
|Basic element support||?|
The browser icons are explained in the below list:
= Microsoft Internet Explorer 6+
= Netscape Communicator 4
= Mozilla and Netscape Navigator 6+
= Opera 7+
= MSN TV (aka. WebTV)
= Konqueror 3.0+