Feature | EPUB 2 | EPUB 3 |
Publication Format | XHTML 1.1 | XHTML5 and HTML5 |
Media Support | Limited to text and static images | Supports audio, video, and interactive elements like JavaScript |
Text Layout | Reflowable text only | Supports both reflowable and fixed-layout formats |
CSS | CSS2 | CSS3 |
Metadata | Basic Dublin Core metadata | Expanded metadata, including EPUB 3-specific metadata properties |
Navigation | Table of Contents (TOC) only | Advanced navigation with multiple navigation documents, landmarks, and page lists |
Media Overlays | Not supported | Supports synchronized media overlays (text and audio synchronization) |
MathML | Not supported | Full support for MathML for mathematical and scientific content |
SVG | Limited support | Full support for SVG, including standalone SVG documents |
Scripting | Limited JavaScript support | Enhanced scripting support using HTML5 and JavaScript |
Font Embedding | Supported | Improved support for font embedding and CSS3 fonts |
Annotations | Not supported | Basic annotation support |
Accessibility | Basic accessibility with alt text | Enhanced accessibility with ARIA roles, improved semantic structure, and better media overlays support |
Package Document | OCF (Open Container Format) with OPF 2.0 | OCF with OPF 3.0, allowing greater flexibility and richer content descriptions |
Content Documents | EPUB Content Documents | Expanded to include EPUB Publications, enabling richer, more interactive content |
Interactive Features | Limited | Enhanced interactive features using JavaScript, HTML5 forms, and CSS animations |
Linking | Basic linking within the document | Advanced linking, including fragment
identifiers and linking to specific locations within resources |