前 言扩展标记语言（Extensible Markup Language，XML)，是目前最有前途的在World Wide Web上保存和传递信息的语言。尽管超文本标记语言（Hypertext Markup Language，HTML）目前是创建Web页的最常用语言，但是它在保存信息方面的能力很有限。-foreword Extensible Markup Language (Extensible Markup Language, XML), is the most promising in the World Wide Web on the preservation and transmission of information language. Although HTML (Hypertext Markup Language, HTML) is the creation of Web pages of the most commonly used language, but it is the preservation of information is very limited.