HTML

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
open	Specifies whether the details should be open (visible to the user) or closed (hidden from the user). 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 open or open="open"). Possible values: [Empty string] open

Global Attributes

The following attributes are standard across all HTML 5 tags.

accesskey	hidden	itemtype
class	id	lang
contenteditable	inert	spellcheck
contextmenu	itemid	style
dir	itemprop	tabindex
draggable	itemref	title
dropzone	itemscope	translate

For a full explanation of these attributes, see HTML 5 global attributes.

Event Handler Content Attributes

Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.
Here are the standard HTML 5 event handler content attributes.

onabort	onerror*	onmousewheel
onblur*	onfocus*	onpause
oncanplay	onformchange	onplay
oncanplaythrough	onforminput	onplaying
onchange	oninput	onprogress
onclick	oninvalid	onratechange
oncontextmenu	onkeydown	onreadystatechange
ondblclick	onkeypress	onscroll
ondrag	onkeyup	onseeked
ondragend	onload*	onseeking
ondragenter	onloadeddata	onselect
ondragleave	onloadedmetadata	onshow
ondragover	onloadstart	onstalled
ondragstart	onmousedown	onsubmit
ondrop	onmousemove	onsuspend
ondurationchange	onmouseout	ontimeupdate
onemptied	onmouseover	onvolumechange
onended	onmouseup	onwaiting

For a full explanation of these attributes, see HTML 5 event handler content attributes.

Also see the HTML 4.01 tags