Table of contents

  1. 1 Introduction
  2. 2 Common infrastructure
  3. 3 Semantics, structure, and APIs of HTML documents
  4. 4 The elements of HTML
  5. 5 Microdata
  6. 6 User interaction
  7. 7 Loading web pages
  8. 8 Web application APIs
  9. 9 Communication
  10. 10 Web workers
  11. 11 Worklets
  12. 12 Web storage
  13. 13 The HTML syntax
  14. 14 The XML syntax
  15. 15 Rendering
  16. 16 Obsolete features
  17. 17 IANA considerations
  18. Index
  19. References
  20. Acknowledgments
  21. Intellectual property rights

Full table of contents

  1. 1 Introduction
    1. 1.1 Where does this specification fit?
    2. 1.2 Is this HTML5?
    3. 1.3 Background
    4. 1.4 Audience
    5. 1.5 Scope
    6. 1.6 History
    7. 1.7 Design notes
      1. 1.7.1 Serializability of script execution
      2. 1.7.2 Compliance with other specifications
      3. 1.7.3 Extensibility
    8. 1.8 HTML vs XML syntax
    9. 1.9 Structure of this specification
      1. 1.9.1 How to read this specification
      2. 1.9.2 Typographic conventions
    10. 1.10 A quick introduction to HTML
      1. 1.10.1 Writing secure applications with HTML
      2. 1.10.2 Common pitfalls to avoid when using the scripting APIs
      3. 1.10.3 How to catch mistakes when writing HTML: validators and conformance checkers
    11. 1.11 Conformance requirements for authors
      1. 1.11.1 Presentational markup
      2. 1.11.2 Syntax errors
      3. 1.11.3 Restrictions on content models and on attribute values
    12. 1.12 Suggested reading
  2. 2 Common infrastructure
    1. 2.1 Terminology
      1. 2.1.1 Parallelism
      2. 2.1.2 Resources
      3. 2.1.3 XML compatibility
      4. 2.1.4 DOM trees
      5. 2.1.5 Scripting
      6. 2.1.6 Plugins
      7. 2.1.7 Character encodings
      8. 2.1.8 Conformance classes
      9. 2.1.9 Dependencies
      10. 2.1.10 Extensibility
      11. 2.1.11 Interactions with XPath and XSLT
    2. 2.2 Policy-controlled features
    3. 2.3 Common microsyntaxes
      1. 2.3.1 Common parser idioms
      2. 2.3.2 Boolean attributes
      3. 2.3.3 Keywords and enumerated attributes
      4. 2.3.4 Numbers
        1. 2.3.4.1 Signed integers
        2. 2.3.4.2 Non-negative integers
        3. 2.3.4.3 Floating-point numbers
        4. 2.3.4.4 Percentages and lengths
        5. 2.3.4.5 Nonzero percentages and lengths
        6. 2.3.4.6 Lists of floating-point numbers
        7. 2.3.4.7 Lists of dimensions
      5. 2.3.5 Dates and times
        1. 2.3.5.1 Months
        2. 2.3.5.2 Dates
        3. 2.3.5.3 Yearless dates
        4. 2.3.5.4 Times
        5. 2.3.5.5 Local dates and times
        6. 2.3.5.6 Time zones
        7. 2.3.5.7 Global dates and times
        8. 2.3.5.8 Weeks
        9. 2.3.5.9 Durations
        10. 2.3.5.10 Vaguer moments in time
      6. 2.3.6 Legacy colors
      7. 2.3.7 Space-separated tokens
      8. 2.3.8 Comma-separated tokens
      9. 2.3.9 References
      10. 2.3.10 Media queries
      11. 2.3.11 Unique internal values
    4. 2.4 URLs
      1. 2.4.1 Terminology
      2. 2.4.2 Parsing URLs
      3. 2.4.3 Dynamic changes to base URLs
    5. 2.5 Fetching resources
      1. 2.5.1 Terminology
      2. 2.5.2 Determining the type of a resource
      3. 2.5.3 Extracting character encodings from meta elements
      4. 2.5.4 CORS settings attributes
      5. 2.5.5 Referrer policy attributes
      6. 2.5.6 Nonce attributes
      7. 2.5.7 Lazy loading attributes
      8. 2.5.8 Blocking attributes
      9. 2.5.9 Fetch priority attributes
    6. 2.6 Common DOM interfaces
      1. 2.6.1 Reflecting content attributes in IDL attributes
      2. 2.6.2 Using reflect in specifications
      3. 2.6.3 Collections
        1. 2.6.3.1 The HTMLAllCollection interface
          1. 2.6.3.1.1 [[Call]] ( thisArgument, argumentsList )
        2. 2.6.3.2 The HTMLFormControlsCollection interface
        3. 2.6.3.3 The HTMLOptionsCollection interface
      4. 2.6.4 The DOMStringList interface
    7. 2.7 Safe passing of structured data
      1. 2.7.1 Serializable objects
      2. 2.7.2 Transferable objects
      3. 2.7.3 StructuredSerializeInternal ( value, forStorage [ , memory ] )
      4. 2.7.4 StructuredSerialize ( value )
      5. 2.7.5 StructuredSerializeForStorage ( value )
      6. 2.7.6 StructuredDeserialize ( serialized, targetRealm [ , memory ] )
      7. 2.7.7 StructuredSerializeWithTransfer ( value, transferList )
      8. 2.7.8 StructuredDeserializeWithTransfer ( serializeWithTransferResult, targetRealm )
      9. 2.7.9 Performing serialization and transferring from other specifications
      10. 2.7.10 Structured cloning API
  3. 3 Semantics, structure, and APIs of HTML documents
    1. 3.1 Documents
      1. 3.1.1 The Document object
      2. 3.1.2 The DocumentOrShadowRoot interface
      3. 3.1.3 Resource metadata management
      4. 3.1.4 Reporting document loading status
      5. 3.1.5 Render-blocking mechanism
      6. 3.1.6 DOM tree accessors
    2. 3.2 Elements
      1. 3.2.1 Semantics
      2. 3.2.2 Elements in the DOM
      3. 3.2.3 HTML element constructors
      4. 3.2.4 Element definitions
        1. 3.2.4.1 Attributes
      5. 3.2.5 Content models
        1. 3.2.5.1 The "nothing" content model
        2. 3.2.5.2 Kinds of content
          1. 3.2.5.2.1 Metadata content
          2. 3.2.5.2.2 Flow content
          3. 3.2.5.2.3 Sectioning content
          4. 3.2.5.2.4 Heading content
          5. 3.2.5.2.5 Phrasing content
          6. 3.2.5.2.6 Embedded content
          7. 3.2.5.2.7 Interactive content
          8. 3.2.5.2.8 Palpable content
          9. 3.2.5.2.9 Script-supporting elements
        3. 3.2.5.3 Transparent content models
        4. 3.2.5.4 Paragraphs
      6. 3.2.6 Global attributes
        1. 3.2.6.1 The title attribute
        2. 3.2.6.2 The lang and xml:lang attributes
        3. 3.2.6.3 The translate attribute
        4. 3.2.6.4 The dir attribute
        5. 3.2.6.5 The style attribute
        6. 3.2.6.6 Embedding custom non-visible data with the data-* attributes
      7. 3.2.7 The innerText and outerText properties
      8. 3.2.8 Requirements relating to the bidirectional algorithm
        1. 3.2.8.1 Authoring conformance criteria for bidirectional-algorithm formatting characters
        2. 3.2.8.2 User agent conformance criteria
      9. 3.2.9 Requirements related to ARIA and to platform accessibility APIs
  4. 4 The elements of HTML
    1. 4.1 The document element
      1. 4.1.1 The html element
    2. 4.2 Document metadata
      1. 4.2.1 The head element
      2. 4.2.2 The title element
      3. 4.2.3 The base element
      4. 4.2.4 The link element
        1. 4.2.4.1 Processing the media attribute
        2. 4.2.4.2 Processing the type attribute
        3. 4.2.4.3 Fetching and processing a resource from a link element
        4. 4.2.4.4 Processing `Link` headers
        5. 4.2.4.5 Early hints
        6. 4.2.4.6 Providing users with a means to follow hyperlinks created using the link element
      5. 4.2.5 The meta element
        1. 4.2.5.1 Standard metadata names
        2. 4.2.5.2 Other metadata names
        3. 4.2.5.3 Pragma directives
        4. 4.2.5.4 Specifying the document's character encoding
      6. 4.2.6 The style element
      7. 4.2.7 Interactions of styling and scripting
    3. 4.3 Sections
      1. 4.3.1 The body element
      2. 4.3.2 The article element
      3. 4.3.3 The section element
      4. 4.3.4 The nav element
      5. 4.3.5 The aside element
      6. 4.3.6 The h1, h2, h3, h4, h5, and h6 elements
      7. 4.3.7 The hgroup element
      8. 4.3.8 The header element
      9. 4.3.9 The footer element
      10. 4.3.10 The address element
      11. 4.3.11 Headings and outlines
        1. 4.3.11.1 Sample outlines
        2. 4.3.11.2 Exposing outlines to users
      12. 4.3.12 Usage summary
        1. 4.3.12.1 Article or section?
    4. 4.4 Grouping content
      1. 4.4.1 The p element
      2. 4.4.2 The hr element
      3. 4.4.3 The pre element
      4. 4.4.4 The blockquote element
      5. 4.4.5 The ol element
      6. 4.4.6 The ul element
      7. 4.4.7 The menu element
      8. 4.4.8 The li element
      9. 4.4.9 The dl element
      10. 4.4.10 The dt element
      11. 4.4.11 The dd element
      12. 4.4.12 The figure element
      13. 4.4.13 The figcaption element
      14. 4.4.14 The main element
      15. 4.4.15 The search element
      16. 4.4.16 The div element
    5. 4.5 Text-level semantics
      1. 4.5.1 The a element
      2. 4.5.2 The em element
      3. 4.5.3 The strong element
      4. 4.5.4 The small element
      5. 4.5.5 The s element
      6. 4.5.6 The cite element
      7. 4.5.7 The q element
      8. 4.5.8 The dfn element
      9. 4.5.9 The abbr element
      10. 4.5.10 The ruby element
      11. 4.5.11 The rt element
      12. 4.5.12 The rp element
      13. 4.5.13 The data element
      14. 4.5.14 The time element
      15. 4.5.15 The code element
      16. 4.5.16 The var element
      17. 4.5.17 The samp element
      18. 4.5.18 The kbd element
      19. 4.5.19 The sub and sup elements
      20. 4.5.20 The i element
      21. 4.5.21 The b element
      22. 4.5.22 The u element
      23. 4.5.23 The mark element
      24. 4.5.24 The bdi element
      25. 4.5.25 The bdo element
      26. 4.5.26 The span element
      27. 4.5.27 The br element
      28. 4.5.28 The wbr element
      29. 4.5.29 Usage summary
    6. 4.6 Links
      1. 4.6.1 Introduction
      2. 4.6.2 Links created by a and area elements
      3. 4.6.3 API for a and area elements
      4. 4.6.4 Following hyperlinks
      5. 4.6.5 Downloading resources
      6. 4.6.6 Hyperlink auditing
        1. 4.6.6.1 The `Ping-From` and `Ping-To` headers
      7. 4.6.7 Link types
        1. 4.6.7.1 Link type "alternate"
        2. 4.6.7.2 Link type "author"
        3. 4.6.7.3 Link type "bookmark"
        4. 4.6.7.4 Link type "canonical"
        5. 4.6.7.5 Link type "dns-prefetch"
        6. 4.6.7.6 Link type "expect"
        7. 4.6.7.7 Link type "external"
        8. 4.6.7.8 Link type "help"
        9. 4.6.7.9 Link type "icon"
        10. 4.6.7.10 Link type "license"
        11. 4.6.7.11 Link type "manifest"
        12. 4.6.7.12 Link type "modulepreload"
        13. 4.6.7.13 Link type "nofollow"
        14. 4.6.7.14 Link type "noopener"
        15. 4.6.7.15 Link type "noreferrer"
        16. 4.6.7.16 Link type "opener"
        17. 4.6.7.17 Link type "pingback"
        18. 4.6.7.18 Link type "preconnect"
        19. 4.6.7.19 Link type "prefetch"
        20. 4.6.7.20 Link type "preload"
        21. 4.6.7.21 Link type "privacy-policy"
        22. 4.6.7.22 Link type "search"
        23. 4.6.7.23 Link type "stylesheet"
        24. 4.6.7.24 Link type "tag"
        25. 4.6.7.25 Link Type "terms-of-service"
        26. 4.6.7.26 Sequential link types
          1. 4.6.7.26.1 Link type "next"
          2. 4.6.7.26.2 Link type "prev"
        27. 4.6.7.27 Other link types
    7. 4.7 Edits
      1. 4.7.1 The ins element
      2. 4.7.2 The del element
      3. 4.7.3 Attributes common to ins and del elements
      4. 4.7.4 Edits and paragraphs
      5. 4.7.5 Edits and lists
      6. 4.7.6 Edits and tables
    8. 4.8 Embedded content
      1. 4.8.1 The picture element
      2. 4.8.2 The source element
      3. 4.8.3 The img element
      4. 4.8.4 Images
        1. 4.8.4.1 Introduction
          1. 4.8.4.1.1 Adaptive images
        2. 4.8.4.2 Attributes common to source, img, and link elements
          1. 4.8.4.2.1 Srcset attributes
          2. 4.8.4.2.2 Sizes attributes
        3. 4.8.4.3 Processing model
          1. 4.8.4.3.1 When to obtain images
          2. 4.8.4.3.2 Reacting to DOM mutations
          3. 4.8.4.3.3 The list of available images
          4. 4.8.4.3.4 Decoding images
          5. 4.8.4.3.5 Updating the image data
          6. 4.8.4.3.6 Preparing an image for presentation
          7. 4.8.4.3.7 Selecting an image source
          8. 4.8.4.3.8 Creating a source set from attributes
          9. 4.8.4.3.9 Updating the source set
          10. 4.8.4.3.10 Parsing a srcset attribute
          11. 4.8.4.3.11 Parsing a sizes attribute
          12. 4.8.4.3.12 Normalizing the source densities
          13. 4.8.4.3.13 Reacting to environment changes
        4. 4.8.4.4 Requirements for providing text to act as an alternative for images
          1. 4.8.4.4.1 General guidelines
          2. 4.8.4.4.2 A link or button containing nothing but the image
          3. 4.8.4.4.3 A phrase or paragraph with an alternative graphical representation: charts, diagrams, graphs, maps, illustrations
          4. 4.8.4.4.4 A short phrase or label with an alternative graphical representation: icons, logos
          5. 4.8.4.4.5 Text that has been rendered to a graphic for typographical effect
          6. 4.8.4.4.6 A graphical representation of some of the surrounding text
          7. 4.8.4.4.7 Ancillary images
          8. 4.8.4.4.8 A purely decorative image that doesn't add any information
          9. 4.8.4.4.9 A group of images that form a single larger picture with no links
          10. 4.8.4.4.10 A group of images that form a single larger picture with links
          11. 4.8.4.4.11 A key part of the content
          12. 4.8.4.4.12 An image not intended for the user
          13. 4.8.4.4.13 An image in an email or private document intended for a specific person who is known to be able to view images
          14. 4.8.4.4.14 Guidance for markup generators
          15. 4.8.4.4.15 Guidance for conformance checkers
      5. 4.8.5 The iframe element
      6. 4.8.6 The embed element
      7. 4.8.7 The object element
      8. 4.8.8 The video element
      9. 4.8.9 The audio element
      10. 4.8.10 The track element
      11. 4.8.11 Media elements
        1. 4.8.11.1 Error codes
        2. 4.8.11.2 Location of the media resource
        3. 4.8.11.3 MIME types
        4. 4.8.11.4 Network states
        5. 4.8.11.5 Loading the media resource
        6. 4.8.11.6 Offsets into the media resource
        7. 4.8.11.7 Ready states
        8. 4.8.11.8 Playing the media resource
        9. 4.8.11.9 Seeking
        10. 4.8.11.10 Media resources with multiple media tracks
          1. 4.8.11.10.1 AudioTrackList and VideoTrackList objects
          2. 4.8.11.10.2 Selecting specific audio and video tracks declaratively
        11. 4.8.11.11 Timed text tracks
          1. 4.8.11.11.1 Text track model
          2. 4.8.11.11.2 Sourcing in-band text tracks
          3. 4.8.11.11.3 Sourcing out-of-band text tracks
          4. 4.8.11.11.4 Guidelines for exposing cues in various formats as text track cues
          5. 4.8.11.11.5 Text track API
          6. 4.8.11.11.6 Event handlers for objects of the text track APIs
          7. 4.8.11.11.7 Best practices for metadata text tracks
        12. 4.8.11.12 Identifying a track kind through a URL
        13. 4.8.11.13 User interface
        14. 4.8.11.14 Time ranges
        15. 4.8.11.15 The TrackEvent interface
        16. 4.8.11.16 Events summary
        17. 4.8.11.17 Security and privacy considerations
        18. 4.8.11.18 Best practices for authors using media elements
        19. 4.8.11.19 Best practices for implementers of media elements
      12. 4.8.12 The map element
      13. 4.8.13 The area element
      14. 4.8.14 Image maps
        1. 4.8.14.1 Authoring
        2. 4.8.14.2 Processing model
      15. 4.8.15 MathML
      16. 4.8.16 SVG
      17. 4.8.17 Dimension attributes
    9. 4.9 Tabular data
      1. 4.9.1 The table element
        1. 4.9.1.1 Techniques for describing tables
        2. 4.9.1.2 Techniques for table design
      2. 4.9.2 The caption element
      3. 4.9.3 The colgroup element
      4. 4.9.4 The col element
      5. 4.9.5 The tbody element
      6. 4.9.6 The thead element
      7. 4.9.7 The tfoot element
      8. 4.9.8 The tr element
      9. 4.9.9 The td element
      10. 4.9.10 The th element
      11. 4.9.11 Attributes common to td and th elements
      12. 4.9.12 Processing model
        1. 4.9.12.1 Forming a table
        2. 4.9.12.2 Forming relationships between data cells and header cells
      13. 4.9.13 Examples
    10. 4.10 Forms
      1. 4.10.1 Introduction
        1. 4.10.1.1 Writing a form's user interface
        2. 4.10.1.2 Implementing the server-side processing for a form
        3. 4.10.1.3 Configuring a form to communicate with a server
        4. 4.10.1.4 Client-side form validation
        5. 4.10.1.5 Enabling client-side automatic filling of form controls
        6. 4.10.1.6 Improving the user experience on mobile devices
        7. 4.10.1.7 The difference between the field type, the autofill field name, and the input modality
        8. 4.10.1.8 Date, time, and number formats
      2. 4.10.2 Categories
      3. 4.10.3 The form element
      4. 4.10.4 The label element
      5. 4.10.5 The input element
        1. 4.10.5.1 States of the type attribute
          1. 4.10.5.1.1 Hidden state (type=hidden)
          2. 4.10.5.1.2 Text (type=text) state and Search state (type=search)
          3. 4.10.5.1.3 Telephone state (type=tel)
          4. 4.10.5.1.4 URL state (type=url)
          5. 4.10.5.1.5 Email state (type=email)
          6. 4.10.5.1.6 Password state (type=password)
          7. 4.10.5.1.7 Date state (type=date)
          8. 4.10.5.1.8 Month state (type=month)
          9. 4.10.5.1.9 Week state (type=week)
          10. 4.10.5.1.10 Time state (type=time)
          11. 4.10.5.1.11 Local Date and Time state (type=datetime-local)
          12. 4.10.5.1.12 Number state (type=number)
          13. 4.10.5.1.13 Range state (type=range)
          14. 4.10.5.1.14 Color state (type=color)
          15. 4.10.5.1.15 Checkbox state (type=checkbox)
          16. 4.10.5.1.16 Radio Button state (type=radio)
          17. 4.10.5.1.17 File Upload state (type=file)
          18. 4.10.5.1.18 Submit Button state (type=submit)
          19. 4.10.5.1.19 Image Button state (type=image)
          20. 4.10.5.1.20 Reset Button state (type=reset)
          21. 4.10.5.1.21 Button state (type=button)
        2. 4.10.5.2 Implementation notes regarding localization of form controls
        3. 4.10.5.3 Common input element attributes
          1. 4.10.5.3.1 The maxlength and minlength attributes
          2. 4.10.5.3.2 The size attribute
          3. 4.10.5.3.3 The readonly attribute
          4. 4.10.5.3.4 The required attribute
          5. 4.10.5.3.5 The multiple attribute
          6. 4.10.5.3.6 The pattern attribute
          7. 4.10.5.3.7 The min and max attributes
          8. 4.10.5.3.8 The step attribute
          9. 4.10.5.3.9 The list attribute
          10. 4.10.5.3.10 The placeholder attribute
        4. 4.10.5.4 Common input element APIs
        5. 4.10.5.5 Common event behaviors
      6. 4.10.6 The button element
      7. 4.10.7 The select element
      8. 4.10.8 The datalist element
      9. 4.10.9 The optgroup element
      10. 4.10.10 The option element
      11. 4.10.11 The textarea element
      12. 4.10.12 The output element
      13. 4.10.13 The progress element
      14. 4.10.14 The meter element
      15. 4.10.15 The fieldset element
      16. 4.10.16 The legend element
      17. 4.10.17 Form control infrastructure
        1. 4.10.17.1 A form control's value
        2. 4.10.17.2 Mutability
        3. 4.10.17.3 Association of controls and forms
      18. 4.10.18 Attributes common to form controls
        1. 4.10.18.1 Naming form controls: the name attribute
        2. 4.10.18.2 Submitting element directionality: the dirname attribute
        3. 4.10.18.3 Limiting user input length: the maxlength attribute
        4. 4.10.18.4 Setting minimum input length requirements: the minlength attribute
        5. 4.10.18.5 Enabling and disabling form controls: the disabled attribute
        6. 4.10.18.6 Form submission attributes
        7. 4.10.18.7 Autofill
          1. 4.10.18.7.1 Autofilling form controls: the autocomplete attribute
          2. 4.10.18.7.2 Processing model
      19. 4.10.19 APIs for the text control selections
      20. 4.10.20 Constraints
        1. 4.10.20.1 Definitions
        2. 4.10.20.2 Constraint validation
        3. 4.10.20.3 The constraint validation API
        4. 4.10.20.4 Security
      21. 4.10.21 Form submission
        1. 4.10.21.1 Introduction
        2. 4.10.21.2 Implicit submission
        3. 4.10.21.3 Form submission algorithm
        4. 4.10.21.4 Constructing the entry list
        5. 4.10.21.5 Selecting a form submission encoding
        6. 4.10.21.6 Converting an entry list to a list of name-value pairs
        7. 4.10.21.7 URL-encoded form data
        8. 4.10.21.8 Multipart form data
        9. 4.10.21.9 Plain text form data
        10. 4.10.21.10 The SubmitEvent interface
        11. 4.10.21.11 The FormDataEvent interface
      22. 4.10.22 Resetting a form
    11. 4.11 Interactive elements
      1. 4.11.1 The details element
      2. 4.11.2 The summary element
      3. 4.11.3 Commands
        1. 4.11.3.1 Facets
        2. 4.11.3.2 Using the a element to define a command
        3. 4.11.3.3 Using the button element to define a command
        4. 4.11.3.4 Using the input element to define a command
        5. 4.11.3.5 Using the option element to define a command
        6. 4.11.3.6 Using the accesskey attribute on a legend element to define a command
        7. 4.11.3.7 Using the accesskey attribute to define a command on other elements
      4. 4.11.4 The dialog element
    12. 4.12 Scripting
      1. 4.12.1 The script element
        1. 4.12.1.1 Processing model
        2. 4.12.1.2 Scripting languages
        3. 4.12.1.3 Restrictions for contents of script elements
        4. 4.12.1.4 Inline documentation for external scripts
        5. 4.12.1.5 Interaction of script elements and XSLT
      2. 4.12.2 The noscript element
      3. 4.12.3 The template element
        1. 4.12.3.1 Interaction of template elements with XSLT and XPath
      4. 4.12.4 The slot element
      5. 4.12.5 The canvas element
        1. 4.12.5.1 The 2D rendering context
          1. 4.12.5.1.1 Implementation notes
          2. 4.12.5.1.2 The canvas state
          3. 4.12.5.1.3 Line styles
          4. 4.12.5.1.4 Text styles
          5. 4.12.5.1.5 Building paths
          6. 4.12.5.1.6 Path2D objects
          7. 4.12.5.1.7 Transformations
          8. 4.12.5.1.8 Image sources for 2D rendering contexts
          9. 4.12.5.1.9 Fill and stroke styles
          10. 4.12.5.1.10 Drawing rectangles to the bitmap
          11. 4.12.5.1.11 Drawing text to the bitmap
          12. 4.12.5.1.12 Drawing paths to the canvas
          13. 4.12.5.1.13 Drawing focus rings
          14. 4.12.5.1.14 Drawing images
          15. 4.12.5.1.15 Pixel manipulation
          16. 4.12.5.1.16 Compositing
          17. 4.12.5.1.17 Image smoothing
          18. 4.12.5.1.18 Shadows
          19. 4.12.5.1.19 Filters
          20. 4.12.5.1.20 Working with externally-defined SVG filters
          21. 4.12.5.1.21 Drawing model
          22. 4.12.5.1.22 Best practices
          23. 4.12.5.1.23 Examples
        2. 4.12.5.2 The ImageBitmap rendering context
          1. 4.12.5.2.1 Introduction
          2. 4.12.5.2.2 The ImageBitmapRenderingContext interface
        3. 4.12.5.3 The OffscreenCanvas interface
          1. 4.12.5.3.1 The offscreen 2D rendering context
        4. 4.12.5.4 Color spaces and color space conversion
        5. 4.12.5.5 Serializing bitmaps to a file
        6. 4.12.5.6 Security with canvas elements
        7. 4.12.5.7 Premultiplied alpha and the 2D rendering context
    13. 4.13 Custom elements
      1. 4.13.1 Introduction
        1. 4.13.1.1 Creating an autonomous custom element
        2. 4.13.1.2 Creating a form-associated custom element
        3. 4.13.1.3 Creating a custom element with default accessible roles, states, and properties
        4. 4.13.1.4 Creating a customized built-in element
        5. 4.13.1.5 Drawbacks of autonomous custom elements
        6. 4.13.1.6 Upgrading elements after their creation
        7. 4.13.1.7 Exposing custom element states
      2. 4.13.2 Requirements for custom element constructors and reactions
      3. 4.13.3 Core concepts
      4. 4.13.4 The CustomElementRegistry interface
      5. 4.13.5 Upgrades
      6. 4.13.6 Custom element reactions
      7. 4.13.7 Element internals
        1. 4.13.7.1 The ElementInternals interface
        2. 4.13.7.2 Shadow root access
        3. 4.13.7.3 Form-associated custom elements
        4. 4.13.7.4 Accessibility semantics
        5. 4.13.7.5 Custom state pseudo-class
    14. 4.14 Common idioms without dedicated elements
      1. 4.14.1 Breadcrumb navigation
      2. 4.14.2 Tag clouds
      3. 4.14.3 Conversations
      4. 4.14.4 Footnotes
    15. 4.15 Disabled elements
    16. 4.16 Matching HTML elements using selectors and CSS
      1. 4.16.1 Case-sensitivity of the CSS 'attr()' function
      2. 4.16.2 Case-sensitivity of selectors
      3. 4.16.3 Pseudo-classes
  5. 5 Microdata
    1. 5.1 Introduction
      1. 5.1.1 Overview
      2. 5.1.2 The basic syntax
      3. 5.1.3 Typed items
      4. 5.1.4 Global identifiers for items
      5. 5.1.5 Selecting names when defining vocabularies
    2. 5.2 Encoding microdata
      1. 5.2.1 The microdata model
      2. 5.2.2 Items
      3. 5.2.3 Names: the itemprop attribute
      4. 5.2.4 Values
      5. 5.2.5 Associating names with items
      6. 5.2.6 Microdata and other namespaces
    3. 5.3 Sample microdata vocabularies
      1. 5.3.1 vCard
        1. 5.3.1.1 Conversion to vCard
        2. 5.3.1.2 Examples
      2. 5.3.2 vEvent
        1. 5.3.2.1 Conversion to iCalendar
        2. 5.3.2.2 Examples
      3. 5.3.3 Licensing works
        1. 5.3.3.1 Examples
    4. 5.4 Converting HTML to other formats
      1. 5.4.1 JSON
  6. 6 User interaction
    1. 6.1 The hidden attribute
    2. 6.2 Page visibility
      1. 6.2.1 The VisibilityStateEntry interface
    3. 6.3 Inert subtrees
      1. 6.3.1 Modal dialogs and inert subtrees
      2. 6.3.2 The inert attribute
    4. 6.4 Tracking user activation
      1. 6.4.1 Data model
      2. 6.4.2 Processing model
      3. 6.4.3 APIs gated by user activation
      4. 6.4.4 The UserActivation interface
      5. 6.4.5 User agent automation
    5. 6.5 Activation behavior of elements
      1. 6.5.1 The ToggleEvent interface
    6. 6.6 Focus
      1. 6.6.1 Introduction
      2. 6.6.2 Data model
      3. 6.6.3 The tabindex attribute
      4. 6.6.4 Processing model
      5. 6.6.5 Sequential focus navigation
      6. 6.6.6 Focus management APIs
      7. 6.6.7 The autofocus attribute
    7. 6.7 Assigning keyboard shortcuts
      1. 6.7.1 Introduction
      2. 6.7.2 The accesskey attribute
      3. 6.7.3 Processing model
    8. 6.8 Editing
      1. 6.8.1 Making document regions editable: The contenteditable content attribute
      2. 6.8.2 Making entire documents editable: the designMode getter and setter
      3. 6.8.3 Best practices for in-page editors
      4. 6.8.4 Editing APIs
      5. 6.8.5 Spelling and grammar checking
      6. 6.8.6 Writing suggestions
      7. 6.8.7 Autocapitalization
      8. 6.8.8 Autocorrection
      9. 6.8.9 Input modalities: the inputmode attribute
      10. 6.8.10 Input modalities: the enterkeyhint attribute
    9. 6.9 Find-in-page
      1. 6.9.1 Introduction
      2. 6.9.2 Interaction with details and hidden=until-found
      3. 6.9.3 Interaction with selection
    10. 6.10 Close requests and close watchers
      1. 6.10.1 Close requests
      2. 6.10.2 Close watcher infrastructure
      3. 6.10.3 The CloseWatcher interface
    11. 6.11 Drag and drop
      1. 6.11.1 Introduction
      2. 6.11.2 The drag data store
      3. 6.11.3 The DataTransfer interface
        1. 6.11.3.1 The DataTransferItemList interface
        2. 6.11.3.2 The DataTransferItem interface
      4. 6.11.4 The DragEvent interface
      5. 6.11.5 Processing model
      6. 6.11.6 Events summary
      7. 6.11.7 The draggable attribute
      8. 6.11.8 Security risks in the drag-and-drop model
    12. 6.12 The popover attribute
      1. 6.12.1 The popover target attributes
      2. 6.12.2 Popover light dismiss
  7. 7 Loading web pages
    1. 7.1 Supporting concepts
      1. 7.1.1 Origins
        1. 7.1.1.1 Sites
        2. 7.1.1.2 Relaxing the same-origin restriction
      2. 7.1.2 Origin-keyed agent clusters
      3. 7.1.3 Cross-origin opener policies
        1. 7.1.3.1 The headers
        2. 7.1.3.2 Browsing context group switches due to opener policy
        3. 7.1.3.3 Reporting
      4. 7.1.4 Cross-origin embedder policies
        1. 7.1.4.1 The headers
        2. 7.1.4.2 Embedder policy checks
      5. 7.1.5 Sandboxing
      6. 7.1.6 Policy containers
    2. 7.2 APIs related to navigation and session history
      1. 7.2.1 Security infrastructure for Window, WindowProxy, and Location objects
        1. 7.2.1.1 Integration with IDL
        2. 7.2.1.2 Shared internal slot: [[CrossOriginPropertyDescriptorMap]]
        3. 7.2.1.3 Shared abstract operations
          1. 7.2.1.3.1 CrossOriginProperties ( O )
          2. 7.2.1.3.2 CrossOriginPropertyFallback ( P )
          3. 7.2.1.3.3 IsPlatformObjectSameOrigin ( O )
          4. 7.2.1.3.4 CrossOriginGetOwnPropertyHelper ( O, P )
          5. 7.2.1.3.5 CrossOriginGet ( O, P, Receiver )
          6. 7.2.1.3.6 CrossOriginSet ( O, P, V, Receiver )
          7. 7.2.1.3.7 CrossOriginOwnPropertyKeys ( O )
      2. 7.2.2 The Window object
        1. 7.2.2.1 Opening and closing windows
        2. 7.2.2.2 Indexed access on the Window object
        3. 7.2.2.3 Named access on the Window object
        4. 7.2.2.4 Accessing related windows
        5. 7.2.2.5 Historical browser interface element APIs
        6. 7.2.2.6 Script settings for Window objects
      3. 7.2.3 The WindowProxy exotic object
        1. 7.2.3.1 [[GetPrototypeOf]] ( )
        2. 7.2.3.2 [[SetPrototypeOf]] ( V )
        3. 7.2.3.3 [[IsExtensible]] ( )
        4. 7.2.3.4 [[PreventExtensions]] ( )
        5. 7.2.3.5 [[GetOwnProperty]] ( P )
        6. 7.2.3.6 [[DefineOwnProperty]] ( P, Desc )
        7. 7.2.3.7 [[Get]] ( P, Receiver )
        8. 7.2.3.8 [[Set]] ( P, V, Receiver )
        9. 7.2.3.9 [[Delete]] ( P )
        10. 7.2.3.10 [[OwnPropertyKeys]] ( )
      4. 7.2.4 The Location interface
        1. 7.2.4.1 [[GetPrototypeOf]] ( )
        2. 7.2.4.2 [[SetPrototypeOf]] ( V )
        3. 7.2.4.3 [[IsExtensible]] ( )
        4. 7.2.4.4 [[PreventExtensions]] ( )
        5. 7.2.4.5 [[GetOwnProperty]] ( P )
        6. 7.2.4.6 [[DefineOwnProperty]] ( P, Desc )
        7. 7.2.4.7 [[Get]] ( P, Receiver )
        8. 7.2.4.8 [[Set]] ( P, V, Receiver )
        9. 7.2.4.9 [[Delete]] ( P )
        10. 7.2.4.10 [[OwnPropertyKeys]] ( )
      5. 7.2.5 The History interface
      6. 7.2.6 The navigation API
        1. 7.2.6.1 Introduction
        2. 7.2.6.2 The Navigation interface
        3. 7.2.6.3 Core infrastructure
        4. 7.2.6.4 Initializing and updating the entry list
        5. 7.2.6.5 The NavigationHistoryEntry interface
        6. 7.2.6.6 The history entry list
        7. 7.2.6.7 Initiating navigations
        8. 7.2.6.8 Ongoing navigation tracking
        9. 7.2.6.9 The NavigationActivation interface
        10. 7.2.6.10 The navigate event
          1. 7.2.6.10.1 The NavigateEvent interface
          2. 7.2.6.10.2 The NavigationDestination interface
          3. 7.2.6.10.3 Firing the event
          4. 7.2.6.10.4 Scroll and focus behavior
      7. 7.2.7 Event interfaces
        1. 7.2.7.1 The NavigationCurrentEntryChangeEvent interface
        2. 7.2.7.2 The PopStateEvent interface
        3. 7.2.7.3 The HashChangeEvent interface
        4. 7.2.7.4 The PageSwapEvent interface
        5. 7.2.7.5 The PageRevealEvent interface
        6. 7.2.7.6 The PageTransitionEvent interface
        7. 7.2.7.7 The BeforeUnloadEvent interface
      8. 7.2.8 The NotRestoredReasons interface
    3. 7.3 Infrastructure for sequences of documents
      1. 7.3.1 Navigables
        1. 7.3.1.1 Traversable navigables
        2. 7.3.1.2 Top-level traversables
        3. 7.3.1.3 Child navigables
        4. 7.3.1.4 Jake diagrams
        5. 7.3.1.5 Related navigable collections
        6. 7.3.1.6 Navigable destruction
        7. 7.3.1.7 Navigable target names
      2. 7.3.2 Browsing contexts
        1. 7.3.2.1 Creating browsing contexts
        2. 7.3.2.2 Related browsing contexts
        3. 7.3.2.3 Groupings of browsing contexts
      3. 7.3.3 Fully active documents
    4. 7.4 Navigation and session history
      1. 7.4.1 Session history
        1. 7.4.1.1 Session history entries
        2. 7.4.1.2 Document state
        3. 7.4.1.3 Centralized modifications of session history
        4. 7.4.1.4 Low-level operations on session history
      2. 7.4.2 Navigation
        1. 7.4.2.1 Supporting concepts
        2. 7.4.2.2 Beginning navigation
        3. 7.4.2.3 Ending navigation
          1. 7.4.2.3.1 The usual cross-document navigation case
          2. 7.4.2.3.2 The javascript: URL special case
          3. 7.4.2.3.3 Fragment navigations
          4. 7.4.2.3.4 Non-fetch schemes and external software
        4. 7.4.2.4 Preventing navigation
        5. 7.4.2.5 Aborting navigation
      3. 7.4.3 Reloading and traversing
      4. 7.4.4 Non-fragment synchronous "navigations"
      5. 7.4.5 Populating a session history entry
      6. 7.4.6 Applying the history step
        1. 7.4.6.1 Updating the traversable
        2. 7.4.6.2 Updating the document
        3. 7.4.6.3 Revealing the document
        4. 7.4.6.4 Scrolling to a fragment
        5. 7.4.6.5 Persisted history entry state
    5. 7.5 Document lifecycle
      1. 7.5.1 Shared document creation infrastructure
      2. 7.5.2 Loading HTML documents
      3. 7.5.3 Loading XML documents
      4. 7.5.4 Loading text documents
      5. 7.5.5 Loading multipart/x-mixed-replace documents
      6. 7.5.6 Loading media documents
      7. 7.5.7 Loading a document for inline content that doesn't have a DOM
      8. 7.5.8 Finishing the loading process
      9. 7.5.9 Unloading documents
      10. 7.5.10 Destroying documents
      11. 7.5.11 Aborting a document load
    6. 7.6 The `X-Frame-Options` header
    7. 7.7 The `Refresh` header
    8. 7.8 Browser user interface considerations
  8. 8 Web application APIs
    1. 8.1 Scripting
      1. 8.1.1 Introduction
      2. 8.1.2 Agents and agent clusters
        1. 8.1.2.1 Integration with the JavaScript agent formalism
        2. 8.1.2.2 Integration with the JavaScript agent cluster formalism
      3. 8.1.3 Realms and their counterparts
        1. 8.1.3.1 Environments
        2. 8.1.3.2 Environment settings objects
        3. 8.1.3.3 Realms, settings objects, and global objects
          1. 8.1.3.3.1 Entry
          2. 8.1.3.3.2 Incumbent
          3. 8.1.3.3.3 Current
          4. 8.1.3.3.4 Relevant
        4. 8.1.3.4 Enabling and disabling scripting
        5. 8.1.3.5 Secure contexts
      4. 8.1.4 Script processing model
        1. 8.1.4.1 Scripts
        2. 8.1.4.2 Fetching scripts
        3. 8.1.4.3 Creating scripts
        4. 8.1.4.4 Calling scripts
        5. 8.1.4.5 Killing scripts
        6. 8.1.4.6 Runtime script errors
        7. 8.1.4.7 Unhandled promise rejections
        8. 8.1.4.8 Import map parse results
      5. 8.1.5 Module specifier resolution
        1. 8.1.5.1 The resolution algorithm
        2. 8.1.5.2 Import maps
        3. 8.1.5.3 Import map processing model
      6. 8.1.6 JavaScript specification host hooks
        1. 8.1.6.1 HostEnsureCanAddPrivateElement(O)
        2. 8.1.6.2 HostEnsureCanCompileStrings(realm, parameterStrings, bodyString, codeString, compilationType, parameterArgs, bodyArg)
        3. 8.1.6.3 HostGetCodeForEval(argument)
        4. 8.1.6.4 HostPromiseRejectionTracker(promise, operation)
        5. 8.1.6.5 HostSystemUTCEpochNanoseconds(global)
        6. 8.1.6.6 Job-related host hooks
          1. 8.1.6.6.1 HostCallJobCallback(callback, V, argumentsList)
          2. 8.1.6.6.2 HostEnqueueFinalizationRegistryCleanupJob(finalizationRegistry)
          3. 8.1.6.6.3 HostEnqueueGenericJob(job, realm)
          4. 8.1.6.6.4 HostEnqueuePromiseJob(job, realm)
          5. 8.1.6.6.5 HostEnqueueTimeoutJob(job, realm, milliseconds)
          6. 8.1.6.6.6 HostMakeJobCallback(callable)
        7. 8.1.6.7 Module-related host hooks
          1. 8.1.6.7.1 HostGetImportMetaProperties(moduleRecord)
          2. 8.1.6.7.2 HostGetSupportedImportAttributes()
          3. 8.1.6.7.3 HostLoadImportedModule(referrer, moduleRequest, loadState, payload)
      7. 8.1.7 Event loops
        1. 8.1.7.1 Definitions
        2. 8.1.7.2 Queuing tasks
        3. 8.1.7.3 Processing model
        4. 8.1.7.4 Generic task sources
        5. 8.1.7.5 Dealing with the event loop from other specifications
      8. 8.1.8 Events
        1. 8.1.8.1 Event handlers
        2. 8.1.8.2 Event handlers on elements, Document objects, and Window objects
          1. 8.1.8.2.1 IDL definitions
        3. 8.1.8.3 Event firing
    2. 8.2 The WindowOrWorkerGlobalScope mixin
    3. 8.3 Base64 utility methods
    4. 8.4 Dynamic markup insertion
      1. 8.4.1 Opening the input stream
      2. 8.4.2 Closing the input stream
      3. 8.4.3 document.write()
      4. 8.4.4 document.writeln()
    5. 8.5 DOM parsing and serialization APIs
      1. 8.5.1 The DOMParser interface
      2. 8.5.2 Unsafe HTML parsing methods
      3. 8.5.3 HTML serialization methods
      4. 8.5.4 The innerHTML property
      5. 8.5.5 The outerHTML property
      6. 8.5.6 The insertAdjacentHTML() method
      7. 8.5.7 The createContextualFragment() method
    6. 8.6 Timers
    7. 8.7 Microtask queuing
    8. 8.8 User prompts
      1. 8.8.1 Simple dialogs
      2. 8.8.2 Printing
    9. 8.9 System state and capabilities
      1. 8.9.1 The Navigator object
        1. 8.9.1.1 Client identification
        2. 8.9.1.2 Language preferences
        3. 8.9.1.3 Browser state
        4. 8.9.1.4 Custom scheme handlers: the registerProtocolHandler() method
          1. 8.9.1.4.1 Security and privacy
          2. 8.9.1.4.2 User agent automation
        5. 8.9.1.5 Cookies
        6. 8.9.1.6 PDF viewing support
    10. 8.10 Images
    11. 8.11 Animation frames
  9. 9 Communication
    1. 9.1 The MessageEvent interface
    2. 9.2 Server-sent events
      1. 9.2.1 Introduction
      2. 9.2.2 The EventSource interface
      3. 9.2.3 Processing model
      4. 9.2.4 The `Last-Event-ID` header
      5. 9.2.5 Parsing an event stream
      6. 9.2.6 Interpreting an event stream
      7. 9.2.7 Authoring notes
      8. 9.2.8 Connectionless push and other features
      9. 9.2.9 Garbage collection
      10. 9.2.10 Implementation advice
    3. 9.3 Cross-document messaging
      1. 9.3.1 Introduction
      2. 9.3.2 Security
        1. 9.3.2.1 Authors
        2. 9.3.2.2 User agents
      3. 9.3.3 Posting messages
    4. 9.4 Channel messaging
      1. 9.4.1 Introduction
        1. 9.4.1.1 Examples
        2. 9.4.1.2 Ports as the basis of an object-capability model on the web
        3. 9.4.1.3 Ports as the basis of abstracting out service implementations
      2. 9.4.2 Message channels
      3. 9.4.3 The MessageEventTarget mixin
      4. 9.4.4 Message ports
      5. 9.4.5 Ports and garbage collection
    5. 9.5 Broadcasting to other browsing contexts
  10. 10 Web workers
    1. 10.1 Introduction
      1. 10.1.1 Scope
      2. 10.1.2 Examples
        1. 10.1.2.1 A background number-crunching worker
        2. 10.1.2.2 Using a JavaScript module as a worker
        3. 10.1.2.3 Shared workers introduction
        4. 10.1.2.4 Shared state using a shared worker
        5. 10.1.2.5 Delegation
        6. 10.1.2.6 Providing libraries
      3. 10.1.3 Tutorials
        1. 10.1.3.1 Creating a dedicated worker
        2. 10.1.3.2 Communicating with a dedicated worker
        3. 10.1.3.3 Shared workers
    2. 10.2 Infrastructure
      1. 10.2.1 The global scope
        1. 10.2.1.1 The WorkerGlobalScope common interface
        2. 10.2.1.2 Dedicated workers and the DedicatedWorkerGlobalScope interface
        3. 10.2.1.3 Shared workers and the SharedWorkerGlobalScope interface
      2. 10.2.2 The event loop
      3. 10.2.3 The worker's lifetime
      4. 10.2.4 Processing model
      5. 10.2.5 Runtime script errors
      6. 10.2.6 Creating workers
        1. 10.2.6.1 The AbstractWorker mixin
        2. 10.2.6.2 Script settings for workers
        3. 10.2.6.3 Dedicated workers and the Worker interface
        4. 10.2.6.4 Shared workers and the SharedWorker interface
      7. 10.2.7 Concurrent hardware capabilities
    3. 10.3 APIs available to workers
      1. 10.3.1 Importing scripts and libraries
      2. 10.3.2 The WorkerNavigator interface
      3. 10.3.3 The WorkerLocation interface
  11. 11 Worklets
    1. 11.1 Introduction
      1. 11.1.1 Motivations
      2. 11.1.2 Code idempotence
      3. 11.1.3 Speculative evaluation
    2. 11.2 Examples
      1. 11.2.1 Loading scripts
      2. 11.2.2 Registering a class and invoking its methods
    3. 11.3 Infrastructure
      1. 11.3.1 The global scope
        1. 11.3.1.1 Agents and event loops
        2. 11.3.1.2 Creation and termination
        3. 11.3.1.3 Script settings for worklets
      2. 11.3.2 The Worklet class
      3. 11.3.3 The worklet's lifetime
  12. 12 Web storage
    1. 12.1 Introduction
    2. 12.2 The API
      1. 12.2.1 The Storage interface
      2. 12.2.2 The sessionStorage getter
      3. 12.2.3 The localStorage getter
      4. 12.2.4 The StorageEvent interface
    3. 12.3 Privacy
      1. 12.3.1 User tracking
      2. 12.3.2 Sensitivity of data
    4. 12.4 Security
      1. 12.4.1 DNS spoofing attacks
      2. 12.4.2 Cross-directory attacks
      3. 12.4.3 Implementation risks
  13. 13 The HTML syntax
    1. 13.1 Writing HTML documents
      1. 13.1.1 The DOCTYPE
      2. 13.1.2 Elements
        1. 13.1.2.1 Start tags
        2. 13.1.2.2 End tags
        3. 13.1.2.3 Attributes
        4. 13.1.2.4 Optional tags
        5. 13.1.2.5 Restrictions on content models
        6. 13.1.2.6 Restrictions on the contents of raw text and escapable raw text elements
      3. 13.1.3 Text
        1. 13.1.3.1 Newlines
      4. 13.1.4 Character references
      5. 13.1.5 CDATA sections
      6. 13.1.6 Comments
    2. 13.2 Parsing HTML documents
      1. 13.2.1 Overview of the parsing model
      2. 13.2.2 Parse errors
      3. 13.2.3 The input byte stream
        1. 13.2.3.1 Parsing with a known character encoding
        2. 13.2.3.2 Determining the character encoding
        3. 13.2.3.3 Character encodings
        4. 13.2.3.4 Changing the encoding while parsing
        5. 13.2.3.5 Preprocessing the input stream
      4. 13.2.4 Parse state
        1. 13.2.4.1 The insertion mode
        2. 13.2.4.2 The stack of open elements
        3. 13.2.4.3 The list of active formatting elements
        4. 13.2.4.4 The element pointers
        5. 13.2.4.5 Other parsing state flags
      5. 13.2.5 Tokenization
        1. 13.2.5.1 Data state
        2. 13.2.5.2 RCDATA state
        3. 13.2.5.3 RAWTEXT state
        4. 13.2.5.4 Script data state
        5. 13.2.5.5 PLAINTEXT state
        6. 13.2.5.6 Tag open state
        7. 13.2.5.7 End tag open state
        8. 13.2.5.8 Tag name state
        9. 13.2.5.9 RCDATA less-than sign state
        10. 13.2.5.10 RCDATA end tag open state
        11. 13.2.5.11 RCDATA end tag name state
        12. 13.2.5.12 RAWTEXT less-than sign state
        13. 13.2.5.13 RAWTEXT end tag open state
        14. 13.2.5.14 RAWTEXT end tag name state
        15. 13.2.5.15 Script data less-than sign state
        16. 13.2.5.16 Script data end tag open state
        17. 13.2.5.17 Script data end tag name state
        18. 13.2.5.18 Script data escape start state
        19. 13.2.5.19 Script data escape start dash state
        20. 13.2.5.20 Script data escaped state
        21. 13.2.5.21 Script data escaped dash state
        22. 13.2.5.22 Script data escaped dash dash state
        23. 13.2.5.23 Script data escaped less-than sign state
        24. 13.2.5.24 Script data escaped end tag open state
        25. 13.2.5.25 Script data escaped end tag name state
        26. 13.2.5.26 Script data double escape start state
        27. 13.2.5.27 Script data double escaped state
        28. 13.2.5.28 Script data double escaped dash state
        29. 13.2.5.29 Script data double escaped dash dash state
        30. 13.2.5.30 Script data double escaped less-than sign state
        31. 13.2.5.31 Script data double escape end state
        32. 13.2.5.32 Before attribute name state
        33. 13.2.5.33 Attribute name state
        34. 13.2.5.34 After attribute name state
        35. 13.2.5.35 Before attribute value state
        36. 13.2.5.36 Attribute value (double-quoted) state
        37. 13.2.5.37 Attribute value (single-quoted) state
        38. 13.2.5.38 Attribute value (unquoted) state
        39. 13.2.5.39 After attribute value (quoted) state
        40. 13.2.5.40 Self-closing start tag state
        41. 13.2.5.41 Bogus comment state
        42. 13.2.5.42 Markup declaration open state
        43. 13.2.5.43 Comment start state
        44. 13.2.5.44 Comment start dash state
        45. 13.2.5.45 Comment state
        46. 13.2.5.46 Comment less-than sign state
        47. 13.2.5.47 Comment less-than sign bang state
        48. 13.2.5.48 Comment less-than sign bang dash state
        49. 13.2.5.49 Comment less-than sign bang dash dash state
        50. 13.2.5.50 Comment end dash state
        51. 13.2.5.51 Comment end state
        52. 13.2.5.52 Comment end bang state
        53. 13.2.5.53 DOCTYPE state
        54. 13.2.5.54 Before DOCTYPE name state
        55. 13.2.5.55 DOCTYPE name state
        56. 13.2.5.56 After DOCTYPE name state
        57. 13.2.5.57 After DOCTYPE public keyword state
        58. 13.2.5.58 Before DOCTYPE public identifier state
        59. 13.2.5.59 DOCTYPE public identifier (double-quoted) state
        60. 13.2.5.60 DOCTYPE public identifier (single-quoted) state
        61. 13.2.5.61 After DOCTYPE public identifier state
        62. 13.2.5.62 Between DOCTYPE public and system identifiers state
        63. 13.2.5.63 After DOCTYPE system keyword state
        64. 13.2.5.64 Before DOCTYPE system identifier state
        65. 13.2.5.65 DOCTYPE system identifier (double-quoted) state
        66. 13.2.5.66 DOCTYPE system identifier (single-quoted) state
        67. 13.2.5.67 After DOCTYPE system identifier state
        68. 13.2.5.68 Bogus DOCTYPE state
        69. 13.2.5.69 CDATA section state
        70. 13.2.5.70 CDATA section bracket state
        71. 13.2.5.71 CDATA section end state
        72. 13.2.5.72 Character reference state
        73. 13.2.5.73 Named character reference state
        74. 13.2.5.74 Ambiguous ampersand state
        75. 13.2.5.75 Numeric character reference state
        76. 13.2.5.76 Hexadecimal character reference start state
        77. 13.2.5.77 Decimal character reference start state
        78. 13.2.5.78 Hexadecimal character reference state
        79. 13.2.5.79 Decimal character reference state
        80. 13.2.5.80 Numeric character reference end state
      6. 13.2.6 Tree construction
        1. 13.2.6.1 Creating and inserting nodes
        2. 13.2.6.2 Parsing elements that contain only text
        3. 13.2.6.3 Closing elements that have implied end tags
        4. 13.2.6.4 The rules for parsing tokens in HTML content
          1. 13.2.6.4.1 The "initial" insertion mode
          2. 13.2.6.4.2 The "before html" insertion mode
          3. 13.2.6.4.3 The "before head" insertion mode
          4. 13.2.6.4.4 The "in head" insertion mode
          5. 13.2.6.4.5 The "in head noscript" insertion mode
          6. 13.2.6.4.6 The "after head" insertion mode
          7. 13.2.6.4.7 The "in body" insertion mode
          8. 13.2.6.4.8 The "text" insertion mode
          9. 13.2.6.4.9 The "in table" insertion mode
          10. 13.2.6.4.10 The "in table text" insertion mode
          11. 13.2.6.4.11 The "in caption" insertion mode
          12. 13.2.6.4.12 The "in column group" insertion mode
          13. 13.2.6.4.13 The "in table body" insertion mode
          14. 13.2.6.4.14 The "in row" insertion mode
          15. 13.2.6.4.15 The "in cell" insertion mode
          16. 13.2.6.4.16 The "in select" insertion mode
          17. 13.2.6.4.17 The "in select in table" insertion mode
          18. 13.2.6.4.18 The "in template" insertion mode
          19. 13.2.6.4.19 The "after body" insertion mode
          20. 13.2.6.4.20 The "in frameset" insertion mode
          21. 13.2.6.4.21 The "after frameset" insertion mode
          22. 13.2.6.4.22 The "after after body" insertion mode
          23. 13.2.6.4.23 The "after after frameset" insertion mode
        5. 13.2.6.5 The rules for parsing tokens in foreign content
      7. 13.2.7 The end
      8. 13.2.8 Speculative HTML parsing
      9. 13.2.9 Coercing an HTML DOM into an infoset
      10. 13.2.10 An introduction to error handling and strange cases in the parser
        1. 13.2.10.1 Misnested tags: <b><i></b></i>
        2. 13.2.10.2 Misnested tags: <b><p></b></p>
        3. 13.2.10.3 Unexpected markup in tables
        4. 13.2.10.4 Scripts that modify the page as it is being parsed
        5. 13.2.10.5 The execution of scripts that are moving across multiple documents
        6. 13.2.10.6 Unclosed formatting elements
    3. 13.3 Serializing HTML fragments
    4. 13.4 Parsing HTML fragments
    5. 13.5 Named character references
  14. 14 The XML syntax
    1. 14.1 Writing documents in the XML syntax
    2. 14.2 Parsing XML documents
    3. 14.3 Serializing XML fragments
    4. 14.4 Parsing XML fragments
  15. 15 Rendering
    1. 15.1 Introduction
    2. 15.2 The CSS user agent style sheet and presentational hints
    3. 15.3 Non-replaced elements
      1. 15.3.1 Hidden elements
      2. 15.3.2 The page
      3. 15.3.3 Flow content
      4. 15.3.4 Phrasing content
      5. 15.3.5 Bidirectional text
      6. 15.3.6 Sections and headings
      7. 15.3.7 Lists
      8. 15.3.8 Tables
      9. 15.3.9 Margin collapsing quirks
      10. 15.3.10 Form controls
      11. 15.3.11 The hr element
      12. 15.3.12 The fieldset and legend elements
    4. 15.4 Replaced elements
      1. 15.4.1 Embedded content
      2. 15.4.2 Images
      3. 15.4.3 Attributes for embedded content and images
      4. 15.4.4 Image maps
    5. 15.5 Widgets
      1. 15.5.1 Native appearance
      2. 15.5.2 Writing mode
      3. 15.5.3 Button layout
      4. 15.5.4 The button element
      5. 15.5.5 The details and summary elements
      6. 15.5.6 The input element as a text entry widget
      7. 15.5.7 The input element as domain-specific widgets
      8. 15.5.8 The input element as a range control
      9. 15.5.9 The input element as a color well
      10. 15.5.10 The input element as a checkbox and radio button widgets
      11. 15.5.11 The input element as a file upload control
      12. 15.5.12 The input element as a button
      13. 15.5.13 The marquee element
      14. 15.5.14 The meter element
      15. 15.5.15 The progress element
      16. 15.5.16 The select element
      17. 15.5.17 The textarea element
    6. 15.6 Frames and framesets
    7. 15.7 Interactive media
      1. 15.7.1 Links, forms, and navigation
      2. 15.7.2 The title attribute
      3. 15.7.3 Editing hosts
      4. 15.7.4 Text rendered in native user interfaces
    8. 15.8 Print media
    9. 15.9 Unstyled XML documents
  16. 16 Obsolete features
    1. 16.1 Obsolete but conforming features
      1. 16.1.1 Warnings for obsolete but conforming features
    2. 16.2 Non-conforming features
    3. 16.3 Requirements for implementations
      1. 16.3.1 The marquee element
      2. 16.3.2 Frames
      3. 16.3.3 Other elements, attributes and APIs
  17. 17 IANA considerations
    1. 17.1 text/html
    2. 17.2 multipart/x-mixed-replace
    3. 17.3 application/xhtml+xml
    4. 17.4 text/ping
    5. 17.5 application/microdata+json
    6. 17.6 text/event-stream
    7. 17.7 web+ scheme prefix
  18. Index
    1. Elements
    2. Element content categories
    3. Attributes
    4. Element interfaces
    5. All interfaces
    6. Events
    7. HTTP headers
    8. MIME types
  19. References
  20. Acknowledgments
  21. Intellectual property rights

1 Introduction

1.1 Where does this specification fit?

This specification defines a big part of the web platform, in lots of detail. Its place in the web platform specification stack relative to other specifications can be best summed up as follows:

1.2 Is this HTML5?

This section is non-normative.

In short: Yes.

In more length: the term "HTML5" is widely used as a buzzword to refer to modern web technologies, many of which (though by no means all) are developed at the WHATWG. This document is one such; others are available from the WHATWG Standards overview.

1.3 Background

This section is non-normative.

HTML is the World Wide Web's core markup language. Originally, HTML was primarily designed as a language for semantically describing scientific documents. Its general design, however, has enabled it to be adapted, over the subsequent years, to describe a number of other types of documents and even applications.

1.4 Audience

This section is non-normative.

This specification is intended for authors of documents and scripts that use the features defined in this specification, implementers of tools that operate on pages that use the features defined in this specification, and individuals wishing to establish the correctness of documents or implementations with respect to the requirements of this specification.

This document is probably not suited to readers who do not already have at least a passing familiarity with web technologies, as in places it sacrifices clarity for precision, and brevity for completeness. More approachable tutorials and authoring guides can provide a gentler introduction to the topic.

In particular, familiarity with the basics of DOM is necessary for a complete understanding of some of the more technical parts of this specification. An understanding of Web IDL, HTTP, XML, Unicode, character encodings, JavaScript, and CSS will also be helpful in places but is not essential.

1.5 Scope

This section is non-normative.

This specification is limited to providing a semantic-level markup language and associated semantic-level scripting APIs for authoring accessible pages on the web ranging from static documents to dynamic applications.

The scope of this specification does not include providing mechanisms for media-specific customization of presentation (although default rendering rules for web browsers are included at the end of this specification, and several mechanisms for hooking into CSS are provided as part of the language).

The scope of this specification is not to describe an entire operating system. In particular, hardware configuration software, image manipulation tools, and applications that users would be expected to use with high-end workstations on a daily basis are out of scope. In terms of applications, this specification is targeted specifically at applications that would be expected to be used by users on an occasional basis, or regularly but from disparate locations, with low CPU requirements. Examples of such applications include online purchasing systems, searching systems, games (especially multiplayer online games), public telephone books or address books, communications software (email clients, instant messaging clients, discussion software), document editing software, etc.

1.6 History

This section is non-normative.

For its first five years (1990-1995), HTML went through a number of revisions and experienced a