- 为何需要微数据
长篇加累版牍,不好理解
微标记来标注其中内容,让其容易识辨

- RDFa
Resource Description Framework
http://www.w3.org/TR/microdata
http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#microdata
http://www.w3.org/TR/rdfa-in-html

--- itemscope 标记

 <articleitemscope><spanitemprop=musician>张学友</span>steps ontothe stage ...<span itemprop=musician>刘德华</span>onthe drums ...<span itemprop=musician>阿宝</span>onthe bass...<span itemprop=musician>周杰伦</span>onthepiano ...</article>

这样就将段落中的内容突出出来

--- 搜索引擎如何解析

http://foolip.org/microdatajs/live/ 在线解析

服务器：

{"items":[{"properties":{"musician":["Pat Metheny","Antonio Sanchez","Steve Rodby","Lyle Mays"}}}]}

所有的prop都被解析

--- Itemprop支持元素

属性 元素
-------------------------------------------------
src audio,embed,iframe,img,source,video
href a,area,link
datetime time
content meta
data object

--- Itemtype 标记

指定数据格式

<articleitemscope itemtype=http://microformats.org/profile/hcalendar#vevent><time itemprop=dtstartdatetime="2010-10-09T20:30:00-04:00">Saturday, October 9th 2010, just before half past eight  in the evening</time><spanitemprop=location>CommunityTheater</span>in<spanitemprop=location>Morristown,NJ</span>...<spanitemprop=summary>Orchestrion</span>...</article>

--- 解析

指定使用日历格式解析数据

BEGIN:VCALENDAR
PRODID:jQuery Microdata
VERSION:2.0
BEGIN:VEVENT
DTSTAMP;VALUE=DATE ‐
TIME:20101227T205755Z
DTSTART;VALUE=DATE ‐
TIME:20101009T2030000400
LOCATION:Community Theater
LOCATION:Morristown\, NJ
SUMMARY:Orchestrion
END:VEVENT
END:VCALENDAR

--- 嵌套使用

<articleitemscope itemtype=http://microformats.org/wiki/hreview><div itemprop=itemitemscope  itemtype=http://microformats.org/profile/hcalendar#vevent><span itemprop=summary>Orchestrion</span>,<timeitemprop=dtstartdatetime="2010-10-09T20:30:00-04:00">October 9th 2010</time>:</div><spanitemprop="summary">A  fascinating evening</span>rated  with<spanitemprop="rating">5</span>stars out of 5 stars.<divitemprop=revieweritemscope itemtype=http://microformats.org/profile/hcard><span  itemprop=fn>NicosThassofilakas</span>,<ahref=http://openweb.ccitemprop=url>openWeb.cc</a></div>
</article>

--- ItemId 属性

用于指定唯一序号

<divitemscope itemtype=http://vocab.example.net/bookitemid="urn:isbn:978 ‐0634066634"><spanitemprop=album>OneQuiet  Night</span>by<spanitemprop=artist>PatMetheny</span>(<timeitemprop=pubdatedatetime=2005‐04‐01>2005</time>,<span  itemprop=pages>88</span>pages)
</div>

--- Itemref 属性

通过使用html标记或者itemid来引用另一个microdata

<article><divid=location><span itemprop=member>PatMetheny</span></div><divid=intro><span  itemprop=member>AntonioSanchez</span><spanitemprop=member>SteveRodby</span><spanitemprop=member>LyleMays</span><spanitemprop=band>PatMetheny Group</span></div></article><divitemscope itemref="location intro"></div>

--- 解析可用字典

http://micoformats.org

- Microdata DOM API

JS完全支持

  var allNodes =document.getItems();var vCards = document.getItems('http://microfomats.org/profile/hcard');

属性 内容
------------------------------------------
itemScope Value of itemscope attribute
itemType Value of itemtype attribute, if present
itemId Value of itemid attribute, if present
itemRef Value of itemref attribute, if present

- 属性方法一览

属性/方法 内容
------------------------------------
length 集合中元素对象
item(index) 访问元素内容
namedItem(name) 使用itemprop中的name属性来访问对象
namedItem(name).values 访问itemprop指定的name中的属性的值
Names DOMStringList所有itemprop的属性值
names.length Itemprop值得长度
names.item(index) 使用itemprop属性值的对象值
names.contains(name) 判断是否包含itemprop属性

--- 小实例

 <sectionitemscope itemtype="http://www.data-vocabulary.org/Person/"><h1itemprop="name">张三</h1><p><imgsrc="1.jpg"alt="张三照片"itemprop="photo"></p><p><ahref="www.zhangsan.org"itemprop="url">张三哥</a></p><dditemprop="address"itemscope  itemtype="http://www.data-vocabulary.org/Person/"><spanitmeprop="region">东城区</span></dd></section>