1. AAC audio file format

    Advanced Audio Coding format, designed to be the successor format to MP3, with generally better sound quality.

  2. AV1 video format

    AV1 (AOMedia Video 1) is a royalty-free video format by the Alliance for Open Media, meant to succeed its predecessor VP9 and compete with the [HEVC/H.265](/hevc) format.

  3. AVIF image format

    A modern image format based on the [AV1 video format](/av1). AVIF generally has better compression than [WebP](/webp), JPEG, PNG and GIF and is designed to supersede them. AVIF competes with [JPEG XL](/jpegxl) which has similar compression quality and is generally seen as more feature-rich than AVIF.

  4. COLR/CPAL(v0) Font Formats

    The COLR table adds support for multi-colored glyphs in a manner that integrates with the rasterizers of existing text engines. COLRv0 only supports pure colors, does not support gradients, transformations and various blending modes.

  5. COLR/CPAL(v1) Font Formats

    COLRv1 is an improved version of COLRv0, this is also part of the OpenType specification. COLRv1 supports additional graphic capabilities. In addition to solid colors, gradient fills can be used, as well as more complex fills using other graphic operations, including affine transformations and various blending modes.

  6. FLAC audio format

    Popular lossless audio compression format

  7. Form attribute

    Attribute for associating input and submit buttons with a form.

  8. Attributes for form submission

    Attributes for form submission that may be specified on submit buttons. The attributes are: `formaction`, `formenctype`, `formmethod`, `formnovalidate`, and `formtarget`

  9. Form validation

    Method of setting required fields and field types without requiring JavaScript. This includes preventing forms from being submitted when appropriate, the `checkValidity()` method as well as support for the `:invalid`, `:valid`, and `:required` CSS pseudo-classes.

  10. HEIF/HEIC image format

    A modern image format based on the [HEVC video format](/hevc). HEIC generally has better compression than [WebP](/webp), JPEG, PNG and GIF. It is hard for browsers to support HEIC because it is [complex and expensive to license](https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding#Patent_licensing). [AVIF](/avif) and [JPEG XL](/jpegxl) provide free licenses and are designed to supersede HEIC.

  11. HEVC/H.265 video format

    The High Efficiency Video Coding (HEVC) compression standard is a video compression format intended to succeed H.264. It is hard for browsers to universally support HEVC because it is [complex and expensive to license](https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding#Patent_licensing). HEVC competes with [AV1](/av1) which has similar compression quality and provides a free license.

  12. JPEG 2000 image format

    JPEG 2000 was built to supersede the original JPEG format by having better compression and more features. [WebP](/webp), [AVIF](/avif) and [JPEG XL](/jpegxl) are all designed to supersede JPEG 2000.

  13. JPEG XL image format

    A modern image format optimized for web environments. JPEG XL generally has better compression than [WebP](/webp), JPEG, PNG and GIF and is designed to supersede them. JPEG XL competes with [AVIF](/avif) which has similar compression quality but fewer features overall.

  14. JPEG XR image format

    JPEG XR was built to supersede the original JPEG format by having better compression and more features. [WebP](/webp), [AVIF](/avif) and [JPEG XL](/jpegxl) are all designed to supersede JPEG XR.

  15. MP3 audio format

    Popular lossy audio compression format

  16. MPEG-4/H.264 video format

    Commonly used video compression format.

  17. Ogg Vorbis audio format

    Vorbis is a free and open source audio format, most commonly used with the Ogg container.

  18. Ogg/Theora video format

    Free lossy video compression format.

  19. Opus audio format

    Royalty-free open audio codec by IETF, which incorporated SILK from Skype and CELT from Xiph.org, to serve higher sound quality and lower latency at the same bitrate.

  20. Wav audio format

    Waveform Audio File Format, aka WAV or WAVE, a typically uncompressed audio format.

  21. WebM video format

    Multimedia format designed to provide a royalty-free, high-quality open video compression format for use with HTML5 video. WebM supports the video codec VP8 and VP9.

  22. WebP image format

    Image format (based on the VP8 video format) that supports lossy and lossless compression, as well as animation and alpha transparency. WebP generally has better compression than JPEG, PNG and GIF and is designed to supersede them. [AVIF](/avif) and [JPEG XL](/jpegxl) are designed to supersede WebP.

  23. WOFF - Web Open Font Format

    Compressed TrueType/OpenType font that contains information about the font's source.

  24. WOFF 2.0 - Web Open Font Format

    TrueType/OpenType font that provides better compression than WOFF 1.0.

  25. audiodata api: format

  26. document api: forms

  27. formdata api

  28. formdataevent api

  29. formdataevent api: formdata

  30. formdata api: @@iterator

  31. formdata api: append

  32. formdata api: append: `filename` parameter

  33. formdata api: delete

  34. formdata api: entries

  35. formdata api: foreach

  36. formdata api: get

  37. formdata api: getall

  38. formdata api: has

  39. formdata api: keys

  40. formdata api: set

  41. formdata api: values

  42. formdata api: available in workers

  43. request api: formdata

  44. response api: formdata

  45. html element: form

  46. html element: form: action

  47. html element: form: name

  48. html element: form: rel

  49. html element: form: target

  50. flif / fuif / pik image formats