该规范称为EPUB规范片段标识符（epubcfi），定义了用于 通过使用片段标识符引用EPUB？出版物中的任意内容。 网络已经证明超链接的概念非常强大，但EPUB出版物 由于缺乏一个有效的链接，超链接带来的许多好处都被剥夺了 标准化的方案连接到它们。尽管已经开发并实施了专有方案 针对单个阅读系统实现，没有普遍理解的语法，就没有 实现跨平台互操作性的方法。可以从中看到显著好处的功能 然而，打破这一障碍是多种多样的:从阅读位置维护到注释 对导航的依赖，指向任何出版物的能力打开了一个全新的维度，而不是 以前可供开发人员和作者使用。 本规范试图通过定义一个可以 唯一标识出版物中的任何位置或简单位置范围:EPUB CFI。下面 考虑因素强烈影响了该方案的设计和范围: ·用于引用内容的机制应该是可互操作的:对阅读的引用 一个阅读系统创建的位置应可供另一个阅读系统使用。 ·对EPUB内容的文档引用应以与现有内容相同的方式启用 超链接可以在整个网络上进行引用。 ·EPUB文件中的每个位置都应该能够识别，而无需修改 文件 ·所有引用相同逻辑位置的片段标识符在比较时应该相等。 ·比较操作，包括排序和比较测试，应该能够 在不访问引用文件的情况下执行。 ·在不访问原始文件的情况下（例如，给定 引用在文件的深处，应该可以生成对文件开头的引用）。 ·标识符解析应合理有效（例如，第一章的处理不合理） 需要解析指向上一章的片段标识符）。 ·引用应该能够通过解析器变体和文档恢复其目标位置 修订版。 ·应支持简单连续范围的表达式。 ·应提供一种可扩展的机制，以适应未来的参考恢复启发 假如

This specification, EPUB Canonical Fragment Identifier (epubcfi), defines a standardized method for referencing arbitrary content within an EPUB？ Publication through the use of fragment identifiers. The Web has proven that the concept of hyperlinking is tremendously powerful, but EPUB Publications have been denied much of the benefit that hyperlinking makes possible because of the lack of a standardized scheme to link into them. Although proprietary schemes have been developed and implemented for individual Reading Systems, without a commonly-understood syntax there has been no way to achieve cross-platform interoperability. The functionality that can see significant benefit from breaking down this barrier, however, is varied: from reading location maintenance to annotation attachment to navigation, the ability to point into any Publication opens a whole new dimension not previously available to developers and Authors. This specification attempts to rectify this situation by defining an arbitrary structural reference that can uniquely identify any location, or simple range of locations, in a Publication: the EPUB CFI. The following considerations have strongly influenced the design and scope of this scheme: · The mechanism used to reference content should be interoperable: references to a reading position created by one Reading System should be usable by another. · Document references to EPUB content should be enabled in the same way that existing hyperlinks enable references throughout the Web. · Each location in an EPUB file should be able to be identified without the need to modify the document. · All fragment identifiers that reference the same logical location should be equal when compared. · Comparison operations, including tests for sorting and comparison, should be able to be performed without accessing the referenced files. · Simple manipulations should be possible without access to the original files (e.g., given a reference deep in a file, it should be possible to generate a reference to the start of the file). · Identifier resolution should be reasonably efficient (e.g., processing of the first chapter is not required to resolve a fragment identifier that points to the last chapter). · References should be able to recover their target locations through parser variations and document revisions. · Expression of simple, contiguous ranges should be supported. · An extensible mechanism to accommodate future reference recovery heuristics should be provided.