The attributes listed below are standard, and are supported by most HTML and XHTML tags. There were some exceptions as late as HTML 4.01 and XHTML 1.1, but HTML5 says they are all supported but not necessarily useful. An attribute is an extension to an element, and is used to include more choices towards the overall functionality. Many can be combined together but most of them only work in specific elements.
Specifies a language code for the content in an element, in XHTML documents. Language code reference. Has no meaning in HTML5.
Keyboard Attributes[]
Attribute
Value
Description
accesskey
character
Specifies a keyboard shortcut to access an element
tabindex
number
Specifies the tab order of an element
Mouse Attributes[]
Attribute
Value
Description
contextmenu
boolean
TBA
draggable
boolean
Determines whether the element is draggable.
dropzone
boolean
TBA
Content Attributes[]
Attribute
Value
Description
contenteditable
boolean
TBA
hidden
boolean
TBA
spellcheck
boolean
TBA
Data Attributes[]
These attributes store data to the page and/or application.
Attribute
Value
Description
Custom Data Attributes
data-*
value
This attribute stores custom data private to the page or application.
Microdata Attributes
itemscope
boolean
TBA
itemtype
URL
TBA
itemid
value
TBA
itemprop
value
TBA
itemref
value
TBA
Inline event handlers[]
Refer to Global Event Attributes for inline event handlers
Every type of event has a corresponding attribute which can set the event-handler of an element for that event type. The attribute's name is "on" followed by the name of the event - for example, "onclick" for click events. However, per Separation of Layers these attributes should not be used except in special cases. See the article on Events for the encouraged solution. Here is a list of event attributes:
