HTML 5 "command" Tag

The HTML <command> tag is used for specifying a command that the user can invoke.

According to the HTML 5 specification:

A command is the abstraction behind menu items, buttons, and links. Once a command is defined, other parts of the interface can refer to the same command, allowing many access points to a single feature to share aspects such as the disabled state.

The <command> tag was introduced in HTML 5.

****The <command> tag is currently not supported in any of the major browsers.

Note: Internet Explorer 9 (not earlier or later versions), supports the <command> tag.

Attributes

HTML tags can contain one or more attributes. Attributes are added to a tag to provide the browser with more information about how the tag should appear or behave. Attributes consist of a name and a value separated by an equals (=) sign, with the value surrounded by double quotes. Here's an example, style="color:black;".
There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.
The attributes that you can add to this tag are listed below.

Element-Specific Attributes

The following table shows the attributes that are specific to this tag/element.

Attribute	Description
type	Specifies the type of command.Possible values: command (default value) checkbox radio
label	Specifies the name of the command, as shown to the user.
icon	Specifies the URI (or IRI) of graphical image that represents the action.
disabled	Specifies if the command is disabled or not.This is a boolean attribute. If the attribute is present, its value must either be the empty string or a  value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace (i.e. either disabled or disabled="disabled"). Possible values: [Empty string] disabled
checked	Indicates whether the command is selected or not.This is a boolean  attribute. If the attribute is present, its value must either be the empty  string or a value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace  (i.e. either checked or checked="checked"). Possible values: [Empty string] checked
radiogroup	Specifies the name of the group of commands that will be toggled  when the command itself is toggled, for commands whose type  attribute has the value "radio".
command	Here's what the HTML5 specification says about the command attribute: If a <command> element slave has a command attribute, and slave is in a Document, and there is an element in that Document whose ID has a value equal to the value of slave's command attribute, and the first such element in tree order, hereafter master, itself defines a command and either is not a<command> element or does not itself have a command attribute, then the master command of slave is master. An element with a command attribute must have a master command and must not have any type, label, icon, disabled, checked, or radiogroupattributes.
title	Specifies a hint describing the command, which can be shown to the user.