下面通过一个例子来解释 FeedSync 协议。 该例子讲述当没有数据一致性冲突发生的的时候，FeedSync 如何工作。

这是一个简单基于RSS协议的XML， 描述我今天的任务列表。

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
  <channel>
    <title>todolist.xml</title>
    <description>Sample to do list</description>
    <link>http://www.example.com/index.html</link>
    <item>
      <title>Pay Bills</title>
      <description>Electric, Gas and Water Bills</description>
    </item>
  </channel>
</rss>

FeedSync 扩展在<item>下面加入了<sx:sync> 标签 以及 <sx:history> 标签

<?xml version="1.0"?>
<rss version="2.0" xmlns:sx="http://feedsync.org/2007/feedsync">
    <channel>
        <title>todolist.xml</title>
        <description>Sample to do list</description>
        <link>http://www.example.com/index.html</link>
        <item>
            <sx:sync id="101" updates="1" deleted="false" noconflicts="false">
                <sx:history sequence="1" when="2007-11-29T06:27:11Z" by="fsRSSConvert.js"/>
            </sx:sync>
            <title>Pay Bills</title>
            <description>Electric, Gas and Water Bills</description>
        </item>
    </channel>
</rss>

假设我有2台电脑（台式机和笔记本）， 在台式电脑A 上我增加了“Buy groceries” 以及“Get car serviced” 任务项； 过了一会儿，我又在笔记本电脑B 上我增加了“Return books to library”以及“Get birthday gift for mother” 任务项。  这时，台式电脑A上的的XML 文件变成了

<item>
      <sx:sync id="101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:11Z" by="fsRSSConvert.js"/>
      </sx:sync>
      <title>Pay Bills</title>
      <description>Electric, Gas and Water Bills</description>
    </item>
    <item>
      <sx:sync id="ep1.100" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:11Z" by="A"/>
      </sx:sync>
      <title>Buy groceries</title>
      <description>Get milk and eggs</description>
    </item>
    <item>
      <sx:sync id="ep1.101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:12Z" by="A"/>
      </sx:sync>
      <title>Get car serviced</title>
      <description>Needs oil change</description>
    </item>
笔记本电脑B上的XML 文件就是

<item>
      <sx:sync id="101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:11Z" by="fsRSSConvert.js"/>
      </sx:sync>
      <title>Pay Bills</title>
      <description>Electric, Gas and Water Bills</description>
    </item>
    <item>
      <sx:sync id="ep2.100" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:12Z" by="B"/>
      </sx:sync>
      <title>Return books to library</title>
      <description>2 books in total</description>
    </item>
    <item>
      <sx:sync id="ep2.101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:12Z" by="B"/>
      </sx:sync>
      <title>Get birthday gift for mother</title>
      <description>She likes blue flowers</description>
    </item>
当两个电脑都做数据同步之后，通过FeedSync协议，服务器上将会对两个XML进行合并，最终形成

<item>
      <sx:sync id="101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:11Z" by="fsRSSConvert.js"/>
      </sx:sync>
      <title>Pay Bills</title>
      <description>Electric, Gas and Water Bills</description>
    </item>
    <item>
      <sx:sync id="ep1.100" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:11Z" by="A"/>
      </sx:sync>
      <title>Buy groceries</title>
      <description>Get milk and eggs</description>
    </item>
    <item>
      <sx:sync id="ep1.101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:12Z" by="A"/>
      </sx:sync>
      <title>Get car serviced</title>
      <description>Needs oil change</description>
    </item>
    <item>
      <sx:sync id="ep2.100" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:12Z" by="B"/>
      </sx:sync>
      <title>Return books to library</title>
      <description>2 books in total</description>
    </item>
    <item>
      <sx:sync id="ep2.101" updates="1" deleted="false" noconflicts="false">
        <sx:history sequence="1" when="2007-11-29T06:27:12Z" by="B"/>
      </sx:sync>
      <title>Get birthday gift for mother</title>
      <description>She likes blue flowers</description>
    </item>