tailieunhanh - A Semantic Web Primer - Chapter 2

Structured Web Documents in XML Ngày nay, HTML (ngôn ngữ đánh dấu siêu văn bản) là ngôn ngữ tiêu chuẩn trong những trang Web được viết. HTML, lần lượt, được bắt nguồn từ SGML (ngôn ngữ đánh dấu tiêu chuẩn tổng quát), một tiêu chuẩn quốc tế (ISO 8879) định nghĩa của độc lập hệ thống thiết bị và phương pháp đại diện thông tin, cả con người và máy có thể đọc được. Tiêu chuẩn như vậy là quan trọng bởi vì chúng cho phép giao tiếp hiệu quả, do đó hỗ trợ tiến bộ công nghệ và hợp. | TLFeBOOK 2 _. . _ v Structured Web Documents in XML Introduction Today HTML hypertext markup language is the standard language in which Web pages are written. HTML in turn was derived from SGML standard generalized markup language an international standard ISO 8879 for the definition of device- and system-independent methods of representing information both human- and machine-readable. Such standards are important because they enable effective communication thus supporting technological progress and business collaboration. In the WWW area standards are set by the W3C World Wide Web Consortium they are called recommendations in acknowledgment of the fact that in a distributed environment without central authority standards cannot be enforced. Languages conforming to SGML are called SGML applications. HTML is such an application it was developed because SGML was considered far too complex for Internet-related purposes. XML extensible markup language is another SGML application and its development was driven by shortcomings of HTML. We can work out some of the motivations for XML by considering a simple example a Web page that contains information about a particular book. h2 Nonmonotonic Reasoning Context-Dependent Reasoning h2 i by b V. Marek b and b M. Truszczynski b i br Springer 1993 br ISBN 0387976892 A typical XML representation of the the same information might look like this TLFeBOOK TLFeBOOK 24 2 Structured Web Documents in XML book title Nonmonotonic Reasoning Context-Dependent Reasoning title author V. Marek author author M. Truszczynski author publisher Springer publisher year 1993 year ISBN 0387976892 ISBN book Before we turn to differences between the HTML and XML representations let us observe a few similarities. First both representations use tags such as h2 and year . Indeed both HTML and XML are markup languages they allow one to write some content and provide information about what role that content plays. Like HTML XML is based on tags. These .