W3cubDocs

/HTML

itemid (attribute)

The itemid global attribute is the unique, global identifier of an item. An itemid attribute can only be specified for an element that has both itemscope and itemtype attributes. Also, itemid can only be specified on elements that possess an itemscope attribute whose corresponding itemtype refers to or defines a vocabulary that supports global identifiers.

The exact meaning of an itemtype's global identifier is provided by the definition of that identifier within the specified vocabulary. The vocabulary defines whether several items with the same global identifier can coexist and, if so, how items with the same identifier are handled.

Note: The Whatwg.org definition specifies that an itemid must be a URL. However, the following example correctly illustrates that a URN may also be used. This inconsistency may reflect the incomplete nature of the Microdata specification.

Example

HTML

<dl itemscope
    itemtype="http://vocab.example.net/book"
    itemid="urn:isbn:0-330-34032-8">
<dt>Title <dd itemprop="title">The Reality Dysfunction
<dt>Author <dd itemprop="author">Peter F. Hamilton
<dt>Publication date
<dd><time itemprop="pubdate" datetime="1996-01-26">26 January 1996</time> </dl>

Structured data

itemscope itemtype: itemid
http://vocab.example.net/book: urn:isbn:0-330-34032-8
itemprop title The Reality Dysfunction
itemprop author
Peter F. Hamilton
itemprop pubdate 1996-01-26

Result

Specifications

Specification Status Comment
itemid WG Note - No longer being actively developed

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/itemid